Flexible instrument

ABSTRACT

A robotic medical system comprises a catheter having an elongated shaft with a plurality of flexible segments spaced apart along the catheter, and a drive unit coupled to the catheter. The catheter may have a plurality of cables respectively terminating at the flexible segments, in which case, the drive unit will be coupled to the plurality of cables. The robotic medical system further comprises a user interface remote from the drive unit and configured for generating at least one command, and an electric controller configured, in response to the command(s), for directing the drive unit to independently bend the flexible segments (e.g., three flexible segments).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of copending application Ser.No. 11/762,772, filed Jun. 13, 2007, which is a continuation ofapplication Ser. No. 10/012,586, filed Nov. 16, 2001 (now U.S. Pat. No.7,371,210), which is a continuation-in-part of application Ser. No.09/827,503, filed Apr. 6, 2001 (now U.S. Pat. No. 6,432,112), which is acontinuation of application Ser. No. 09/746,853, filed Dec. 21, 2000(now U.S. Pat. No. 6,692,485), which is a divisional of application Ser.No. 09/375,666, filed Aug. 17, 1999 (now U.S. Pat. No. 6,197,017), whichis a continuation of application Ser. No. 09/028,550, filed Feb. 24,1998 (now abandoned). The present application is a continuation-in-partof application Ser. No. 09/783,637, filed Feb. 14, 2001 (now abandoned),which is a continuation of PCT/US00/12553, filed May 9, 2000, which isthe non-provisional of Application No. 60/133,407, filed May 10, 1999.The present application is a continuation-in-part of PCT/US01/11376,filed Apr. 6, 2001, which is a continuation of application Ser. Nos.09/746,853, filed Dec. 21, 2000 (now U.S. Pat. No. 6,692,485), and09/827,503, filed Apr. 6, 2001 (now U.S. Pat. No. 6,432,112). Thepresent application is a continuation-in-part of application Ser. Nos.09/746,853, filed Dec. 21, 2000 (now U.S. Pat. No. 6,692,485),09/827,503, filed Apr. 6, 2001 (now U.S. Pat. No. 6,432,112), and09/827,643, filed Apr. 6, 2001 (now U.S. Pat. No. 6,554,844), which isthe non-provisional of Application Nos. 60/257,869, filed Dec. 21, 2000,and 60/195,264, filed Apr. 7, 2000, and is also a continuation-in-partof PCT/US00/12553, filed May 9, 2000, from which application Ser. No.09/783,637, filed Feb. 14, 2001 (now abandoned), claims priority.

The present application is related in subject matter to Application Nos.60/293,346, filed May 24, 2001, 60/279,087, filed Mar. 27, 2001,60/313,496, 60/313,497, and 60/313, 495, filed Aug. 21, 2001, 60/269,203and 60/269,200, filed Feb. 15, 2001, 60/276,151, 60/276,217, 60/276,086,and 60/276,152, filed Mar. 15, 2001, 60/257,816, 60/257,868, 60/257,867,and 60/257,869, filed Dec. 21, 2000; and application Ser. Nos.:10/014,143 (now U.S. Pat. No. 6,775,582), 10/012,845 (now U.S. Pat. No.7,169,141), 10/008,964 (now abandoned), 10/013/046 (now abandoned),10/011,450 (now abandoned), 10/008,457 (now U.S. Pat. No. 6,949,106),10/008,871 (now U.S. Pat. No. 6,843,793), 10/023,024 (now abandoned),10/011,371 (now U.S. Pat. No. 7,090,683), 10/011,449 (now abandoned),10/010,150 (now U.S. Pat. No. 7,214,230), 10/022,038 (now abandoned),and 10/012,586, filed Nov. 16, 2001; 11/762,768 (now U.S. Pat. No.7,918,861), 11/762,770 (now U.S. Pat. No. 7,867,241), filed Jun. 13,2007, 11/762,773 (now U.S. Pat. No. 7,905,828), 11/762,774 (now U.S.Pat. No. 7,713,190), and 11/762,777 (now U.S. Pat. No. 7,775,972), filedJun. 14, 2007. The foregoing applications and patents are herebyincorporated herein by reference in their entireties.

FIELD OF THE INVENTION

The present invention relates in general to a remote controlled flexibleinstrument comprising a flexible shaft, for introduction into a bodycavity or body vessel to perform a medical procedure.

BACKGROUND OF THE INVENTION

Catheters are used extensively in the medical field in various types ofprocedures, including invasive procedures. Minimally invasive surgeryinvolves operating through small incisions, through which instrumentsare inserted. These incisions are typically 5 mm to 10 mm in length.Minimally invasive surgery is typically less traumatic than conventionalsurgery, due, in part, to the significant reduction in incision size.Furthermore, hospitalization is reduced and recovery periods shortenedas compared with conventional surgery techniques. Catheters may betailored to a particular size or form, depending on the incision and thesize of the body cavity or lumen.

Due to the small size of the incision, the bulk of the surgery is notvisible. Although the surgeon can have visual feedback from the surgicalsite via a video camera or endoscope inserted into the patient, or viaradiological imaging or ultrasonic scanning, the ability to control therelatively simple laparoscopic instruments remains difficult. Even withgood visual feedback, the surgeon's tactile and positional senses arephysically removed from the operative site, rendering endoscopicprocedures slow and clumsy.

Current instrumentation, with forceps, scissors, etc., inserted into thebody at the end of long slender push rods is not fully satisfactory. Theuse of such conventional instrumentation increases operative time, andpotentially heightens risk. For example, tissue may be injured when thelaparoscopic tool moves outside the visual field. Moreover, there arelimitations on the type and complexity of procedures that may beperformed laparoscopically due, in part, to the limitations on theinstruments that are used.

Development work has been undertaken to investigate the use of roboticwork in surgery. Typically, these robotic systems use arms that reachover the surgical table and manipulate surgical instruments. The knownrobotic systems are large, clumsy to operate and relatively expensive tomanufacture. The presence of a robot at the surgical site is problematicparticularly when the robot is large and may impede access to thepatient during surgery.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, a robotic medical systemincludes a support that is positionable relative to a patient table; acarriage assembly removably mounted to the support; a flexible guideshaft mounted on the carriage assembly and having a distal endconfigured for being disposed at a predetermined location in a patient'sbody; a distal tool coupled to the flexible guide shaft and configuredfor performing a medical procedure in the patient's body; and a driveunit operatively coupled to the flexible guide shaft through thecarriage assembly to control the movement of the flexible guide shaft inat least one degree-of-freedom. By way of non-limiting example, thesupport may comprise a proximal end assembly configured for mounting tothe patient table. By way of another non-limiting example, the carriageassembly may comprise at least one rail and a carriage slidably disposedon the at least one rail, and wherein the flexible guide shaft iscoupled to the carriage, and wherein the drive unit is operativelycoupled to the distal tool through the carriage assembly to therebycontrol actuation of the distal tool. By way of further non-limitingexample, the at least one degree-of-freedom may include linear motion offlexible guide shaft relative to the support.

The robotic medical system may further comprise a remote controllerconfigured for directing the drive unit to control the movement of theflexible guide shaft in the at least one degree-of-freedom. By way ofnon-limiting example, the remote controller may have a user interfacefor receiving commands from a user, wherein movements of the flexibleguide shaft correspond to movements made at the user interface.

In another embodiment, a robotic medical system includes a support armthat is positionable relative to a patient table; a carriage assemblyremovably mounted to the support arm; a surgical instrument mounted tothe carriage assembly, the surgical instrument carrying a distal toolconfigured for performing a medical procedure on a patient; a drive unitconfigured operatively coupled to the surgical instrument to control themovement of the surgical instrument in at least one degree-of-freedom;and a remote controller configured for directing the drive unit tocontrol the movement of the surgical instrument in the at least onedegree-of-freedom. The drive unit may be further operatively coupled tothe distal tool to thereby control actuation of the distal tool. The atleast one degree-of-freedom may include linear movement of the surgicalinstrument relative to the support. The remote controller may have auser interface for receiving commands from a user, wherein movements ofthe surgical instrument correspond to movements made at the userinterface. The surgical instrument may comprise a flexible guide shaftmounted on the carriage assembly, the instrument having a distal endconfigured for being disposed at a predetermined location in a patient'sbody.

BRIEF DESCRIPTION OF THE DRAWINGS

Numerous other objects, features and advantageous of the inventionshould now become apparent upon a reading of the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a simplified block diagram illustrating basic components of asystem constructed in accordance with the present invention;

FIG. 2 illustrates further details of input devices at the master unit;

FIG. 3 is a schematic diagram illustrating one embodiment of the presentinvention in which the flexible instrument system includes multipleseparate nested catheters;

FIGS. 3A-3C illustrate different forms of catheter control in accordingwith aspects of the present invention;

FIG. 4 is an illustrative diagram showing the use of the catheter of thepresent invention in connection with mitral valve repair;

FIG. 5 is schematic diagram of the catheter system of the presentinvention as deployed through the urethra for a surgical procedure inthe bladder;

FIG. 6 is a perspective view of one embodiment of a system embodying thecatheter apparatus of the present invention;

FIG. 7 is a more detailed perspective view of the catheter apparatus;

FIG. 8 is an enlarged view of a portion of the catheter apparatusparticularly at the distal end section thereof;

FIG. 9 is a cross-sectional view through the catheter apparatus as takenalong line 9-9 of FIG. 7;

FIG. 10 is a cross-sectional view through the catheter apparatus as thedistal end section thereof, as taken along line 10-10 of FIG. 7;

FIG. 11 is a cross-sectional view similar to that illustrated in FIG. 9for an alternate embodiment of the invention depicting dual-directionflexing;

FIG. 12 is one design of tool construction in accordance with thepresent invention employing inner and outer catheters and inner andouter cables;

FIG. 13 is a schematic diagram of the tool or mini-tool showing certainparameters relating to position control;

FIG. 14 is a block diagram of the controller used with the teleroboticsystem of this invention;

FIG. 15 is a block diagram of further details of the controllerparticularly details of the module board;

FIG. 16 is a block diagram of the control algorithm in accordance withthe present invention;

FIG. 17 is a schematic diagram illustrating one mechanism for providingmitral valve repair employing a ring mechanism;

FIG. 18 illustrates schematically the concept of the present inventionin connection with mitral valve repair;

FIG. 19 is a diagram of a heart muscle illustrating the position of themitral valve;

FIG. 20 illustrates further detail of the mitral valve construction aswell as the catheter and tool used in the procedure;

FIG. 21 is a more detailed cross-sectional drawing of the portion of themechanical member, particularly the means for tightening the retainingmeans;

FIG. 22 shows further details of the structure of FIG. 21;

FIG. 23 is a schematic illustration of a section of the mitral valvering showing the fiber and the securing of one end of the fiber;

FIG. 24 illustrates somewhat further detail of a means for retaining thecatheter in position;

FIG. 25 is a diagram illustrating alternate means for holding thecatheter in place;

FIG. 26 illustrates a view of a mitral valve;

FIG. 27 is a schematic diagram of the mitral valve indicating the ringarea and leaflets;

FIG. 28 is a schematic illustration showing the mitral valveconstruction and a mechanical member for retaining and tightening;

FIG. 29 is schematic diagram of another technique for mitral valverepair employing a wire to be tightened like a lasso;

FIG. 30 is a schematic diagram illustrating a catheter and toolconstruction containing a tether cable and anchor elements within theinner catheter;

FIG. 30A shows a cable termination tool for crimping;

FIG. 30B shows a tool for cutting;

FIG. 31 illustrates a staple array of the present invention;

FIG. 32 illustrates the mitral valve construction as well as the stapleapparatus and technique of the present invention;

FIG. 33 is an illustration of the staple array when applied and securedto the valve annulus;

FIG. 34 is a schematic illustration of an alternate embodiment for thestaple array;

FIGS. 35A and 35B illustrate another version of the invention whereinthe guide catheter is robotic;

FIG. 36 schematically represents a system of the present invention forrepairing a mitral valve;

FIG. 36A shows a pin for anchoring;

FIG. 37 illustrates the anchoring system engaged with the mitral valve;

FIG. 38 illustrates another version in accordance with the inventionemploying a balloon with the balloon in a deflated state;

FIG. 39 schematically represents portions of the heart muscle and thepositioning of the balloon relative to the mitral valve;

FIG. 40 illustrates the balloon in its inflated state positioned at themitral valve;

FIGS. 41A-41D depict still another form of catheter in accordance withthe present invention;

FIG. 42 is a perspective view of another embodiment of the presentinvention;

FIG. 42A is an enlarged detail perspective view of the tool;

FIG. 43 is an exploded perspective view of, in particular, theinterlocking modules of the flexible instrument system of FIG. 42;

FIG. 44 is a partially broken away rear elevational view of theinterlocking modules as seen along line 44-44 of FIG. 42;

FIG. 45 is a cross-sectional side view through the interconnectingmodules and as taken along line 45-45 of FIG. 42;

FIG. 46 is a cross-sectional plan view through the instrument moduletaken along line 46-46 of FIG. 45;

FIG. 47 is a cross-sectional plan view taken through the base module ofthe system of FIG. 42, and as taken along line 47-47 of FIG. 45;

FIG. 48 is a cross-sectional end view taken along line 48-48 of FIG. 47;

FIG. 48A is a cross-sectional view taken along line 48A-48A of FIG. 48;

FIG. 48B is a fragmentary plan view of a drive wheel engagement slot byitself as taken along line 48B-48B of FIG. 48A; and

FIG. 49 is a schematic perspective view showing mechanical cablingbetween the drive unit and the flexible instrument system.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a system for remotely controlling aflexible instrument for use in medical applications, typically foroperative or other medical procedures. The flexible instrument comprisesa shaft or a tube of sufficient dimensions for passing through a smallincision or natural body lumen or cavity and ultimately, for positioninga distal end of the shaft within the body at an internal target(operative) site. The flexible instrument can also support a tool at itsdistal end to allow more intricate medical procedures. A user or surgeoncan control the position of the shaft from a master station, allowingoperation from another part of the operating room, or even from anotherroom or another building. In one aspect of the invention, the shaft cancomprise one or more flexible segments, which a user can controllablybend, providing finer control in directing the shaft toward the targetsite. The control can result in, for example, a deflection or turning ofthe shaft, for guiding this shaft through or within various bodycavities or lumens. The controllable bending is also useful for moreprecise positioning of a distal end of the flexible instrument at adesired operative site.

Preferably, the flexible instrument is used to perform minimallyinvasive procedures. “Minimally invasive procedure,” refers herein to asurgical procedure in which a surgeon operates through small cut orincision, the small incision being sufficiently necessary to access theoperative site. In one embodiment, the incision length ranges from 1 mmto 20 mm in diameter, preferably from 5 mm to 10 mm in diameter. Thisprocedure contrasts those procedures requiring a large cut to access theoperative site. Thus, the flexible instrument is preferably used forinsertion through such small incisions and/or through a natural bodylumen or cavity, if necessary, so as to locate the catheter at aninternal target site for a particular surgical or medical procedure.Examples of such minimally invasive procedures include intravascularprocedures, such as the repair of a cardiac valve. The introduction ofthe flexible instrument into the anatomy may be by percutaneous orsurgical access to a lumen or vessel, or by introduction through anatural orifice in the anatomy.

FIG. 1 is a block diagram schematically illustrating the three maincomponents of the remote control system of the present invention. Asurgeon or user can input control actuations at master station 1,typically through an input device (not shown). Slave station 3 isseparate and remote from the master station and controls the motion ofthe flexible instrument, in accordance with the user input from masterstation 1. Master station 1 and slave station 3 may be in relativelyclose proximity to each other, such as in the same operating room, orcan be displaced from each other by miles. Controller 2 provides atelecommunications or electronic communications link coupled between themaster station and the slave station. Controller 2 typically includes acomputer. Controller 2 receives a command from the input device ofmaster station 1 and relays this command to slave station 3.

FIG. 6 is a schematic of the remote control system of the presentinvention. The system includes: (1) A master station comprising a userinterface or surgeon's interface 11; (2) A slave station comprising aflexible instrument including shaft 30 which supports tool 18. Shaft 30is connected to and is controllable from mechanically drivable mechanism26, which in turn is engageably received by receiver 24, both of whichare mechanically driven by drive unit 13, (alternatively mechanicaldrive 13); and (3) a controller or computation system 12 to translate auser's commands from user interface 11 to drive unit 13, which thendrives the articulations of shaft 30 and tool 18. FIG. 6 illustrates asystem where a user or surgeon can control shaft 30 and tool 18 bymanipulating interface handles 30A of user interface 11. The movement ofhandle 30A causes responsive movement of tool 18 through thecoordinating action of computation system 12. For example, tool 18 canbe a pair of graspers, scissors, staplers, etc. and manipulation ofhandle 30A can cause the jaws of tool 18 to open and close.

Surgeon's interface 11 is in electrical communication with computingsystem 12, which is, in turn, in electrical communication with driveunit 13. In one embodiment, drive unit 13 comprises a plurality ofmotors. The drive unit 13 is in mechanical communication with shaft 30via conduit 23, which houses a plurality of mechanical cables driven bythe plurality of motors in drive unit 13. In one embodiment, drive unit13 is solely in mechanical communication with shaft 30. Because of themechanical communication with shaft 30, the electromechanical componentsin drive unit 13 are disposed in an area remote from the operative site,and preferably in an area outside the sterile field. Preferably, objectsthat are difficult to sterilize, e.g. motors or electromechanicalcomponents, are kept at a sufficient distance from the patient to avoidcontamination. This distance is readily ascertainable by doctors,nurses, and other appropriate medical professionals. In one embodiment,the sterile field has the rest surface of the operating table as itslower boundary. Thus, drive unit 13 is preferably located below theplane of the sterile field, i.e. below the rest surface of the operatingtable. The patient or subject may be further protected from drive unit13 with a sterile barrier, such as a sterile cloth. With respect to thedrive unit, such as drive unit 13 in FIG. 6, reference is made toco-pending provisional application No. 60/279,087, which is incorporatedby reference herein. In accordance with the system of FIG. 6, all of thedrive motors in drive unit 13 are disposed away from the sterile fieldand thus the need for a sterile barrier is eliminated. Furthermore,since all of the motors and electronics are within a single,self-contained unit, design, testing and manufacturing of the system isgreatly simplified.

Accordingly, one aspect of the present invention provides a drive unitcapable of remotely driving articulation of a flexible instrument, wherethe drive unit is remote from the subject and the flexible instrument.The slave station of the present invention employs, to a large part, amechanical arrangement that is effected remotely and includes mechanicalcables and flexible conduits coupling to a remote motor drive unit. Thisprovides the advantage that the instrument is purely mechanical and doesnot need to be contained within a sterile barrier. The instrument may beautoclaved, gas sterilized or disposed in total or in part.

In FIG. 6, drive unit 13 mechanically drives the flexible instrument(comprising shaft 30 and tool 18) through conduit 23, receiver 24 andmechanically drivable mechanism 26 (alternatively known as mechanicallydrivable interface or shaft mount). Conduit 23 houses a plurality ofseparate mechanical cables to mechanically connect drive unit 13 withreceiver 24. The mechanical cables physically contact and drive themotions of shaft 30 and tool 18. Conduit 23 is engageable anddisengageable with drive unit 13, i.e. attachable and detachable (seediscussion of FIG. 49, below). Although two conduits 23 are depictedhere, it is understood that more or fewer conduits may be used,depending on the particular application. In one embodiment, drive unit13 comprises a plurality of motors, which drive the mechanical cablesextending through conduit 23 and terminating at receiver 24. Receiver 24interlockably receives mechanically drivable interface 26, which engagesa separate set of cables extending through shaft 30 and at least onecable line operating tool 18. Thus, engaging drivable interface 26 withreceiver 24 provides a mechanical (physical) connection from drive unit13 to control certain motions of shaft 30 and tool 18. Receiver 24,which is supported by a carriage, is capable of moving along a linearpath represented by the arrow 22 via rails 25.

Cables in conduit 23 also mechanically drives the translation ofreceiver 24 along rails 25. The rails, and thus the linear translationextend at an acute angle with respect to the operating table, as well asthe subject. This angular arrangement disposes the flexible instrumentsystem in a convenient position over the patient. This arrangement alsominimizes the number of components that operate within the sterilefield, as drive unit 13 is maintained at a location remote from thesterile field.

FIG. 49 shows a schematic perspective view of the cabling pathway formechanically coupling one of an array of motors of a drive unit with atool supported on a distal end of a shaft. In general, the cablingpathway comprising a plurality of mechanical cables extends from thedrive unit to the receiver. Another separate set of mechanical cablesconnects the mechanically drivable mechanism, situated at a proximal endof the shaft, to the tool and any controlled flexible segmentspositioned along the shaft. Interlocking the receiver with themechanically drivable mechanism results in connecting the two separatesets of mechanical cables, thereby extending the cabling pathway fromthe drive unit to the distal end of the shaft. Thus, each of themechanically drivable mechanism and the receiver can be considered as acoupler, which interlocks or couples with each other.

More specifically, FIG. 49 shows drive motor 675 positioned within adrive unit, such as drive unit 13 of FIG. 6. The first cabling pathwaycomprises a set of cabling, which engages with and extends from drivemotor 675 through idler pulley 682. The cables continue through idlerpulleys 630 and 632 to drive wheel 622, which resides in receiver 506(equivalent to receiver 24 of FIG. 6). A second separate set of cablesextends about the drive wheel 624, guided by cam 626 and continuesthrough flexible instrument shaft 528. Tool 534 links to shaft 528 viajoint 601, which provides a wrist pivot about axis 532 in the directionof arrows J4. The two separate sets of cables are interlocked byinterlocking drive wheel 622 of receiver 506 with drive wheel 624 ofmechanically drivable mechanism 526 (equivalent to drivable mechanism 26of FIG. 6). Specifically, the interlocking involves slotting a blade 606into a corresponding slot within wheel 624 (see further discussion ofFIG. 43 below).

In one embodiment, the interlocking mechanism can comprise a magneticattachment, where a first series of magnets in the mechanically drivablemechanism interacts with a second series of magnets in the receiver.Each series of magnets can couple with the mechanical cables.

FIG. 49 also shows the output of motor 675 at a coupler pulley 677,which is adapted to rotate with an output shaft of the motor. Therotational arrow 680 indicates this rotation.

For the sake of simplicity, FIG. 49 only illustrates one cablingpathway. It can be appreciated that several other cabling pathways canbe constructed and arranged to control other motions of the shaft andtool through other motors of the drive unit.

Regarding the interface 11, computer system 12 and drive unit 13,reference is also made to co-pending application PCT Serial No.PCT/US00/12553 filed May 9, 2000, and U.S. Provisional Application Ser.No. 60/279,087 filed Mar. 27, 2001, both of which are incorporated byreference herein in their entirety.

A more detailed discussion of the master station, the slave station andcomputation system or controller 12 is provided below.

Master Station

FIG. 2 schematically depicts the components of master station 1. Masterstation 1 can include any one or a combination of input devices A-E anda display F. Input device A is a point-and-touch device. Input device Bis a computer mouse. Input device C is a pointing device that may employa pen or stylus. Input device D is a joystick. Input device E is a handinterface, that provides finer control of the shaft, or a toolpositioned at the distal end of the shaft.

In one embodiment, input device E features handles that control themotion of the shaft and a tool. Referring back to FIG. 6, the masterstation features input device 11 comprising handles 30A. Handles 30A areheld by the surgeon, who can then torque, translate or rotate cathetermember 30 and tool 18 by performing the corresponding motions on handles30A. A rotation of a handle 30A via rotation of the surgeon's hand cancontrol rotation of, for example, the outer shaft 32 about the co-axis.Flexing or bending of flexible section 42 can be controlled by thesurgeon flexing his hand at the wrist and activating flex cable 52, asshown in FIG. 8 (see discussion of FIG. 8, below). A surgeon canmanipulate tool 18 by, for example, closing and opening the jaws ofhandles 30A to simulate opening and closing of jaws of tool 18.

Reference may also be made to application Ser. No. 10/008,457, filedNov. 16, 2001 (now U.S. Pat. No. 7,371,210), which discloses otherdetails of a master station input device (master positioner) that may beused in carrying out the control described herein.

Display F provides a direct video image of the site surrounding thedistal end of the shaft. An endoscope supporting a camera is insertedinto the body of a subject, providing the video feed of the operativesite. The camera can be mounted on or housed at the distal end of theshaft. The camera can provide a view of the operative site, or may bepositioned away from the site to provide additional perspective on thesurgical operation.

Other detection systems may be used for providing different imagesuseful in assisting the surgeon in performing the medical procedure.Thus, various signals may be utilized in conjunction with or inalternative to the video image, such as ultrasound (echocardiography,Doppler ultrasound), angiography, electrophysiology, radiology, ormagnet resonance imaging (MRI). Also, an audio signal could be used forguiding the shaft. These detection techniques can be operated with theflexible instrument of the present invention to enhance guidance of theshaft to the site as well as manipulation at the site.

In association with the input devices of FIG. 2, there are variousfeedback techniques can be used for feeding certain parameters sensed atthe slave station back to the master station. The following areparameters that may be sensed, including but not limited to: 1. Force.2. Position. 3. Vibration. 4. Acoustics, auditory. 5. Visual. 6.Neurological stimulus. 7. Electropotential 8. Biochemical sensing.Controller

As discussed previously, FIG. 6 illustrates a computer system 12, whichinterfaces the surgeon interface 11 and drive unit 13 of the slavestation. The drive unit 13 contains a series of motors that controlcables coupled by way of conduit 23 to control certain movements of thecatheter apparatus. The controller 12, depicted in FIG. 6 essentiallylinks the slave station to the surgeon interface. The user input deviceelectronically sends commands, which are translated by the controllerand sent to drive unit 13. Drive unit 13 then mechanically effects themotion of the shaft, particularly the flexible segment and the tool.

FIGS. 14 and 15 are block diagrams of an embodiment of a motor controlsystem that may be employed in a drive unit of the present invention.Regarding the master station side, there is at least one positionencoder associated with each of the degrees-of-motion ordegrees-of-freedom. At least some of these motions are associated with amotor that may be represented by a combination of motor and encoder on acommon shaft. Thus, controlling the motor ultimately controls suchparameters as a force feedback to the master station. The present systemcan comprise a multiaxis, high performance motor control system, whichcan support anywhere from 8 to 64 axes simultaneously using eithereight-bit parallel or pulse width modulated (PWM) signals. The motorsthemselves may be direct current, direct current brushless or steppermotors with a programmable digital filter/commutator. Each motoraccommodates a standard incremental optical encoder.

The block diagram of FIG. 14 represents the basic components of thesystem. Host computer 700 is connected by digital bus 702 to interfaceboard 704. Host computer 700 can be, for example, an Intelmicroprocessor based personal computer (PC) at a control stationpreferably running a Windows NT program communicating with the interfaceboard 704 by way of a high-speed PCI bus 702 (5.0 KHz for eight channelsto 700 Hz for 64 channels) The PC communicates with a multi-channelcontroller electronic card, providing up to 28 axes of motion control,each with a 1.5 kHz sampling rate. The controller is efficient, scalableand robust.

Communication cables 708 intercouple interface board 704 to eightseparate module boards 706. Interface board 704 can be a conventionalinterface board for coupling signals between digital bus 702 andindividual module boards 706. Each module board 706 includes four motioncontrol circuits 710, as illustrated in FIG. 15. Each circuit 710 canbe, for example, a Hewlett-Packard motion control integrated circuit,such as an IC identified as HCTLL1100.

FIG. 15 depicts a further sub unit of this system, particularly a poweramplifier sub unit 712. Power amplifier sub unit 712 is based onNational Semiconductor's H-bridge power amplifier integrated circuitsfor providing PWM motor command signals. Power amplifier 712 isassociated with each of the blocks 710, which couples to a motor X.Associated with motor X is encoder Y. Although the connections are notspecifically set forth, it is understood that signals intercouplebetween block 710 and interface 704 as well as via bus 702 to hostcomputer 700.

The motor control system may be implemented in two ways. In the firstmethod the user may utilize the four types of control modes provided bythe motor control sub unit 706: positional control; proportionalvelocity control; trapezoidal profile control; and integral velocitycontrol. The use of any one of these modes can involve simply specifyingdesired positions or velocities for each motor, and necessary controlactions are computed by motion control IC 710 of the motor control subunit, thereby greatly reducing the complexity of the control systemsoftware. However, in the case where none of the onboard control modesare appropriate for the application, the user may choose the secondmethod in which the servo motor control software is implemented at thePC control station. Appropriate voltage signal outputs for each motorare computed by the PC control station and sent to the motorcontrol/power amplifier unit (706, 712). Even if the computation load ismostly placed on the PC control station's CPU, the use of highperformance computers as well as high speed PCI bus for data transfercan overcome this problem.

FIG. 16 describes the overview of the control algorithm for the presentinvention, mapping out motions of the catheter to that of the surgeon'sinterface handle in three-dimensional space. Such precise mapping cancreate the feel of the tool being an extension of the surgeon's ownhands. The control algorithm can assume that both the surgeon'sinterface as well as the catheter always starts at a predefined positionand orientation, and once the system is started, it repeats a series ofsteps at every sampling. The predetermined positions and orientations,relate to the initial positioning at the master station.

First, the joint sensors (box 435), which are optical encoders in thepresent embodiment, of the surgeon's interface system are read, and viaforward kinematics (box 410) computation of the interface system, thecurrent positions (see line 429) and orientations (see line 427) of theinterface handle can be performed. The translational motion of thesurgeon's hand motion is scaled (box 425) whereas the orientations arekept identical, resulting in desired positions (see line 432) andorientations (see line 434) of the catheter's tool. The results are theninputted into the inverse kinematics algorithms for the catheter's tool,and finally the necessary joint angles and insertion length of thecatheter system are determined. The motor controller (box 420) thencommands the corresponding motors to positions such that the desiredjoint angles and insertion length are achieved.

FIG. 16 provides an initial start position for the handle, indicated atbox 440. The output of box 440 couples to a summation device 430. Theoutput of device 430 couples to scale box 425. Initial handle position440 is established by first positioning the handles at the masterstation so as to establish an initial master station handle orientationin three dimensional space. Initial handle position 440 is then comparedto the current handle position at device 430. The output from device 430is then scaled by box 425 to provide the desired tool position on line432 coupled to the catheter inverse kinematics box 415.

Slave Station

The slave station comprises a flexible instrument, e.g. a shaftoptionally supporting a tool at its distal end, for insertion into asubject. In one embodiment, the flexible instrument is a catheter.“Catheter” as defined herein refers to a shaft adapted for, but notnecessarily limited to, insertion into a subject, and more particularlyfor insertion into natural body lumens, canals, vessels, passageways,cavities or orifices. The shaft is typically tubular, but any elongateshaft may be adaptable for insertion into the subject. The shaft can besolid or hollow. A subject can be a human, an animal, or even individualorgans or tissues that are dead or living.

The introduction of the flexible instrument into the human or animalbody, may be by percutaneous or surgical access to a lumen or vessel, orby introduction through a natural orifice in the body. In this regard,examples of natural lumens include body vessels such as a blood vessel(artery, chamber of the heart or vein), urinary system vessels (renalcollection ducts, calix, ureter, bladder or urethra), hepatobilliaryvessels (hepatic and pancreatic ducts, chyle ducts; common or cysticduct), gastrointestinal tract (esophagus, stomach, small and largeintestine, cecum and rectum), gynecological tract (cervix, uterus,fallopian tube or milk ducts and mammary canals of breast), nasopharynx(eustacean tube, sinuses, pharynx, larynx, trachea, bronchus,bronchiole, tear duct) seminal vesicle, spinal canal, or ventricles ofthe brain. Examples of a natural orifice include oral, rectal, nasal,otic, optic, or urethral orifices.

The shaft can be constructed from a standard 9 French (2.67 mm diameter)coronary guiding catheter.

The shaft may support various forms of tools, typically at its distalend. As depicted in FIG. 6, a user can manipulate tool 18 along a singleaxis of motion where tool 18 is, for example, a grasper, scissors orgeneral mechanism (such as a stapler or clip applier). It is easilyunderstood by those of ordinary skill in the art, however, that toolsmay be located at a position other than the distal end of the shaft.Preferably the tools aid in carrying out various surgical or medicalprocedures, including, but not limited to: 1. Grasp; 2.Cut/lyse/puncture; 3. fill/drain; 4. Secure (suture, staple, anchor); 5.Implant, i.e., any procedure that leaves an object in the body afterwithdrawal of the flexible instrument; 6. Remove; 7. Deliver e.g.drug/therapeutic agents; 8.

Hemostasis; 9. Anastomosis; 10. Repair/reconstruct; 11.Dilate/constrict/occlude; 12. Retraction, e.g. backward or inwardmovement of an organ or part; 13. Coagulate; 14. Laser application; 15.Heat/cool;

Exemplary objects implanted in a subject include staples, tacks,anchors, screws, stents, sutures, and a variety of other objectsimplanted by physicians and medical professionals.

The procedure of delivering (procedure 7, above) can further includedelivery of agents including, but not limited to: 1. Adhesives. 2.Cryonics. 3. Drugs. 4. Biologic agents. 5. Radioactive elements. 6.Bulking agents.

Furthermore, the flexible instrument can be used as a sensor. Parametersthat may be sensed include, but are not limited to: 1. Force. 2.Pressure. 3. Electrophysiological signals. 4. Chemical, oxygen, Ph,blood gas. 5. Temperature. 6. Vibration.

The slave station also comprises a drive unit capable of articulatingthe flexible instrument, particularly the shaft and the tool. The driveunit is to drivably coupled to a receiver for receiving the mechanicallydrivable mechanism. In one embodiment, this coupling occurs via cables.The drive unit is electronically controllable from the master station,as there is an electronic link between the drive unit and a user inputdevice of the master station.

When the receiver receives the mechanically drivable mechanism, thedrive unit then has a direct pathway for controlling operation of theshaft and tool. If the shaft has a controlled flexible segment, thedrive unit is capable of activating or bending the flexible segment viathe mechanically drivable mechanism, for actuation of the shaft, thetool and positioning of the tool at an operative site within thesubject. In one embodiment, drive unit is capable of bending theflexible segment via a first set of cables which couple the drive unitto the receiver, and a second set of cables which drivably couple themechanically drivable mechanism to the flexible segment and the tool.

One aspect of the present invention provides a remote controlled outer(guide) catheter having a distal end disposed at or in an area about anoperative site, preferably in the immediate area of an operative site. Acoaxial inner (working) catheter nested within the outer catheter canthen be used to perform the surgical or medical procedure. Previoussurgical procedures involve insertion of a trocar or cannula into thesubject at a relatively short depth to provide an opening for receipt ofthe catheter, which is then guided to the operative site. Typically thecatheter is not disposed at the immediate area around the operative ortarget site. Thus, if the surgeon needs a second catheter, the firstcatheter must be withdrawn and the second catheter is guided to thetarget site. Such repeated insertions can aggravate trauma experiencedby the patient.

The feature of the present invention, on the other hand, employs anouter catheter disposed at the target site, which allows more than oneshaft to be inserted and withdrawn with minimal irritation or traumaexperienced at the passageway leading to the operative site. In oneembodiment, the outer catheter housing a coaxial inner catheter isdisposed at the target site. The inner catheter can immediately functionat the operative site. If a second inner catheter is required, the firstinner catheter can be quickly withdrawn through the outer guide catheterand the second inner catheter inserted through the outer catheter withminimal injury to the subject.

A feature of this aspect of the present invention allows coaxialmultiple shafts to be remote controlled independently of each other.FIG. 3 depicts a system of remote controlled coaxial catheters. Thissystem employs three coaxial or nested catheters L1-L3. Dashed line Irepresents an incision or entry point of the patient. FIG. 3 alsoillustrates computer controls C1-C3, which are outside of and remotefrom the patient. “Remote from the patient” refers herein to anylocation outside the sterile field. Computer controls C1-C3 areassociated with corresponding actuators A1, A2 and A3, (i.e. driveunits) which in turn are associated with shafts L1-L3, respectively.Thus, in FIG. 3, for example, the controller C1 controls an actuator A1which, in turn, controls a certain action or movement of the outer shaftL1. Those of ordinary skill in the art would readily appreciate thatonly one computer can be used with software capable of independentlycontrolling actuators A1-A3. In another embodiment, shafts L1-L3 can beindependently controlled by one actuator, which independently drivesspecific cables leading to each of shafts L1-L3. Ultimately, the presentinvention allows shafts L1-L3 to be remote controlled independently fromeach other. For example, shaft L1 can remain stationary while shaft L2undergoes linear translations or rotations about the co-axis. The distalend of shaft L3 can also carry out these motions as well as a bend orflex independent of shafts L1 or L2. Shaft L2 can be controlled to, forexample, provide a rotational movement so as to enable rotation of adistal tool. The control of a tool supported at a distal end of a shaftis independent of the motions of shafts L1-L3. Alternatively, all shaftsL1-L3 can undergo a simultaneous bend or deflection at a singleoperative segment or flexible segment, labeled as O in FIG. 3.

FIG. 7 illustrates the outer and inner shafts. In FIG. 7, shaft 30comprises an outer shaft 32 housing and coaxial with inner shaft 34.Outer shaft 32 and inner shaft 34 extend from and within mechanicallydrivable interface 26. Interface 26 mechanically couples a drive unit(shown in FIG. 6) with shaft 30. Interface 26 further comprises a seriesof control elements, such as pulleys 64 and 72, which run cable lines 52and 28, and gears 60 and 68 for controlling rotation of the shafts.

The rotation of outer shaft 32 and inner shaft 34 about the co-axis canbe controlled independently. Control element 60, or gear 60 in interface26 encircles outer shaft 30 and controls the rotational position ofguide shaft 32 in the direction indicated by rotational arrow 65.

Gear 68 in interface 26 encircles inner shaft 34. Control element 68controls the rotational position of the inner shaft 34 in the directionindicated by rotational arrow 69. Rotational arrows 65 and 69 indicaterotation about the “shaft lumen axis”, i.e. the axis tangential to thecross section of the shaft lumen.

If a tool were supported at the distal end of inner shaft 34, controlelement 68 would control the rotational position of the tool about theshaft lumen axis as well. If the distal end were flexed, the shaft wouldcurve and rotation of the shaft would cause the tool to trace a circle,and not cause the tool to rotate about its internal axis. As describedbelow, another control can be positioned in the mechanically drivableinterface for solely controlling the tool independent of the shaftcontrols.

Another aspect of the present invention provides a remote controlledflexible instrument capable of controlled bending, as controlled by auser at a master station. A flexible instrument comprises a shaft havingat least one section that is flexible. “Flexible” refers herein to amaterial that is inherently and sufficiently deformable to readily passatraumatically through a natural body lumen, cavity, vessel, orifice andthe like. In one embodiment, the shaft is sufficiently flexible toreadily flex and/or conform to a pathway in an anatomic vessel, lumen,cavity or the like. Non-flexible or rigid catheters can be distinguishedfrom flexible instruments by the following test. By knowing thedimensions of a rigid catheter and the point of entry into the subject,one can calculate the position of the catheter end point inside thesubject. In contrast, even if the dimensions and point of entry of aflexible shaft were known, the position of its end point within thesubject cannot be calculated with precision because the flexible shaftmay bend.

Flexible instruments of the present invention can also be distinguishedfrom other known catheters that mimic bending motions solely through aseries of rigid sections linked by joints. Thus, a “bend” is not theresult of a deformation of the catheter material but by the pivoting orrotation of two rigid sections about a joint. In contrast, flexibleinstruments of the present invention include at least one flexiblesegment that is bendable without requiring the use of joints. Thebending is remotely controlled, allowing deflection at these flexiblesegments away from the lumen axis of the segment. Bending in this senseis possible by choice of inherent flexibility of the instrument coupledwith an induced deflection at the flexible segment Inherent flexibilitycan be achieved by choice of a deformable material, such as Inherentflexibility can also be achieved by designed construction using a morerigid material, for example carving out segments of the material, i.e.slotting the material, such that the material is sufficiently thin forbending. Of course, the flexible instrument can comprise rotatable orpivotable joints, but the flexible capability is not the result ofemploying such joints, but by the deformability of the shaft material.In one embodiment, the bending is remotely controlled via a drive unitdrivably coupled to the receiver for receiving a mechanically drivablemechanism or shaft mount. The shaft mount is then drivably coupled tothe controlled flexible segment, thereby providing a drivable bendingmechanism.

Those of ordinary skill in the art can appreciate that the shaft can betailored for a particular body lumen. Factors of the shaft constructioninclude resiliency of the walls of the lumen, curvature of thepassageway, location of the target site, diameter of the lumen, etc. Forexample, a shaft for passing through a colon can be, but is notnecessarily, manufactured from a material that is less deformable than ashaft for passing through a small, delicate blood vessel. Lumens thatpresent passageways of high curvature may also require a more easilydeformable, and thus more flexible, shaft than does a relativelystraight lumen. Deformability of the shaft can also be tailored byvarying the dimensions, particularly the diameter, of the shaft.

In this aspect of the invention, a user can controllably bend or flex atleast a section of the flexible instrument. In one embodiment, thiscontrolled bend can be provided by a shaft having at least one flexiblesegment, alternatively a controlled flexible segment. By manipulatingcontrols at the master station, a user can induce a bend in the shaft atthe flexible segment. Preferably, the bend at the flexible segment isactuated mechanically, thus distinguishing this aspect of the presentinvention from prior art catheters where the bends are inducedelectrically. For example, U.S. Pat. No. 5,238,005 describes a bendingmechanism caused by varying the electrical resistance through a cathetermaterial having a negative coefficient. Heating one area of a catheterby increasing its electrical resistance results in contraction of thatarea, causing the catheter to deflect toward the contracted area. Incontrast, the present catheter responds to mechanical forces.

FIGS. 7 and 8 illustrate one embodiment of a controlled flexiblesegment. FIG. 7 shows controlled flexible segment 42 residing betweenproximal end 36 and distal end 38 of shaft 30. It is understood,however, that flexible segment 42 can be positioned on any portion ofshaft 30. FIG. 8 provides an expanded view of flexible segment 42 andillustrates one construction of flexible segment 42. Here, flexiblesegment 42 is constructed by providing inner shaft 34 as a flexiblematerial nested within outer shaft 32. Outer shaft 34 is split intorigid proximal and distal sections 36 and 38, both encircling innershaft 34. Thus, flexible segment 42 is the gap between proximal anddistal sections 36 and 38. Shrink-wrap pieces 44 and 45 extend over therespective facing ends of the proximal and distal shaft sections 36 and38 and adhere these facing ends to the flexible inner shaft.

Alternatively, flexible segment 42 may be in the form of a metal coil ofdiameter similar to the diameter of outer shaft sections 36 and 38.

Although FIG. 8 illustrates outer shaft 32 as being rigid, it can beappreciated that outer shaft 32 can be constructed of a flexiblematerial as well, although its flexibility is preferably less than thatof inner shaft 34.

Referring to both FIGS. 7 and 8, the bending of flexible segment 42 iscontrolled through flex wire 52 extending from mechanically drivablemechanism 26 and through flexible segment 42, terminating at point 54 ofdistal end 38 (see FIG. 8). Flex wire 52 is preferably disposed betweeninner shaft 34 and outer shaft 32. FIG. 8 shows termination point 54residing on the outer surface of distal end 38, although conceivablyother surfaces of distal end 38 can serve as termination points. Theother end wire 52 resides within drivable mechanism 26 on control pulley64. Turning pulley 64 has the effect of pulling wire 52 in a directionparallel to shaft 30 pointing towards drivable mechanism 26. Becausewire 52 is terminated at 54, this pull causes the distal shaft section38 to deflect in a direction indicated by the arrow 55, as shown in FIG.7.

More than one flex wire can be spaced about the circumference of outershaft 32 to allow bending along multiple directions different from arrow55 yet orthogonal to shaft 30. For example, FIG. 11 illustrates anembodiment where two cables actuate bending the bending. FIG. 11 is across-sectional view of outer shaft 32 receiving inner shaft 34 attermination point 52. Two cables 52 A and 52 B terminate on outer 32 onopposite sides of distal shaft section 38. Cables 52A and 52B may bemanipulated so as to deflect the distal shaft section in oppositedirections, in a manner described previously. Those of ordinary skill inthe art can readily appreciate that employing multiple cables results ina shaft capable of deflecting in any number of directions.

If inner shaft 34 supports a tool at its distal end, the bendingmotions, along with the rotation about the co-axis, serves to place thetool at any place in three-dimensional space. Another control element,i.e. pulley 72 controls cable 28, which extends through the hollow areaof inner shaft 34, thereby allowing control of a specific tooloperation. Depending on the complexity of the device, one or more cablesleading to the tool may be required. In one embodiment, FIG. 12 depictsa distal end of shaft 30, showing operative segment o (e.g. flexiblesegment 42) and tool 18. FIG. 12 shows two coaxial catheters includingan outer shaft O1 (such as outer shaft 32) and inner shaft O2 (such asinner shaft 34). Also disclosed are two stainless steel cables,including outer cable O3 and inner cable O4. Outer shaft O1 providestranslational and rotary motion. Outer cable O3, which is disposedbetween outer and inner shafts O1 and O2, provides the lateral rotation(or yaw motion) of tool 18. Inner shaft O2 rotates tool 18 and innercable O4 actuates the jaws of tool 18. The tool of FIG. 12 provides asingle degree-of-freedom in order to actuate a gripper, scissors orgeneric mechanism (such as a stapler or clip applier). An example may bea bi-directional gripper 5 mm in length and 2.67 in diameter.

In one embodiment, the system comprising the flexible instrumentcomprises tool or mini-tool (18), the operative segment (42), thecatheter stem (32, 34), the coupler (24, 26) comprising the mechanicallydrivable mechanism 26 and the receiver 24, the drive unit (13), thecontroller (12) and the surgeon's interface (11). The coupler provides atranslational degree-of-freedom achieved by using a sliding mechanism,i.e. rails 25, onto which the coupler is mounted, as illustrated in FIG.6. The operative or controlled flexible segment provides a number ofarticulations in order to position and orient tool 18. The catheter (30)has four (4) degrees-of-freedom, i.e. one translation and threerotations, as shown in FIG. 7. A fifth degree-of-freedom may be providedby the actuation of the mini-tool, as tool 18 can provide at least asingle axis of motion for a grasper, scissors or general mechanism (suchas a stapler or clip applier). The combination of one translation andtwo rotations allows the operative segment to arbitrarily position themini-tool in three dimensional space. A final degree-of-freedom rotatesthe mini-tool axially.

The following describes the mathematical mapping of the physician'scommand input to the motion of the catheter system. FIG. 13schematically illustrates the various degrees of freedom by which thecatheter can be manipulated, particularly the axial and lateralrotations, or the translation motion allowing independent control of thetool position within the surgical space, as well as axial rotation ofthe tool. For example, the system of FIG. 6 provides a physician withseven independent command inputs, including position (χ_(i), γ_(i),z_(i)), orientation (θ_(i), ω_(i), ψ_(i)) and tool grip angle α_(i). Thecontroller calculates the position of the five (5) independentdegrees-of-freedom of the catheter system, given by (χ_(c), θ_(c),ω_(c), ψ_(c), α_(c)), by determining the position (x, y, z) of the tool,given by χ=χ_(c)+r cos ω_(c), γ=−r sin ω_(c) sin θ_(c), z=r sin ω_(c)cos θ_(c)ψ=ψ_(c)α=α_(c), where χ_(c), θ_(c), ω_(c), ψ_(c), α_(c) are theindependent inputs to the catheter system, and r is the distance fromthe lateral joint to tip of the mini-tool. The resulting position isχ_(c)=χ−r cos ψ_(c), θ_(c), =tan⁻¹(−y/z), ω_(c)=sin⁻¹(z/r cos θ_(c)),ψ_(c)=ψ, α_(c)=α. If λ is chosen as a scaling value, the followingmapping between command input and independent catheter input isx_(c)=λ_(i)−r cos ω_(c) θ_(c)=tan⁻¹(−y_(i)/z_(i)), ω_(c)=sin⁻¹(λz_(i)/rcos θ_(c)), ψ_(c), =ψ, α_(c)=α. It is noted that the axial rotation andgrip position are not scaled.

FIG. 42 is a perspective view of another embodiment of the slave stationfor a remote controlled flexible instrument. FIG. 42 depicts flexibleinstrument system 500 supported from support bracket 502, which extendto the operating table (see FIG. 6). Usually the support bracket issupported from the side of the operating table and may be adjustable inposition relative to the operating table, to dispose system 500 in aconvenient position over the patient. In one embodiment, bracket 502 issecured to the operating table at one end. The other end of bracket 502supports the entire flexible instrument by means of a two-piecestructure similar to that described in copending U.S. ProvisionalApplication Ser. No. 60/279,087 filed Mar. 27, 2001. A knob may beprovided on support base 504, not shown in FIG. 42. Once the supportbase 504 is fixed to the support bracket 502, then the flexibleinstrument system is maintained in a fixed position at base 504,providing a stable and steady structure during the medical procedure.Like FIG. 6, system 500 can be positioned at an acute angle with respectto the operating table.

Flexible instrument system 500 comprises flexible instrument 510 havinga shaft 528 extending to mechanically drivable mechanism 526, whichinterlocks with base (or receiver) 506. Base 506 is supported oncarriage 508. Carriage 508 in turn is adapted for linear translation andsupported by elongated rails 512 and 514. Rails 512 and 514 terminate atone end via end piece 516, which provides further support. Support base504 terminates rails 512 and 514 at their other end. Carriage 508includes bearings or bushings 509 that support the carriage from rails512 and 514.

Flexible instrument system 500 employs two separate cable bundles formechanically driving the flexible instrument along rails 512 and 514.Pulley 521 (dotted outline), residing within carriage control module520, receives a first pair of cables 518. Pulley 521 also receives asecond set of cable (see cabling sections 513 and 515 of correspondingFIG. 43), which runs through carriage 508 to a further pulley 522supported by end piece 516. The second set of cables controls thetranslational motion of carriage 508 and terminates at point 519 (seeFIG. 45).

FIG. 42 also shows a set of cables 524 for driving control elements,e.g. pulleys within receiver 506. These control elements move the shaftand the tool in several degrees-of-freedom. Arrow J1 indicates thelinear translation via module 520. Rotational arrow J2 indicatesrotation of flexible shaft 528 of flexible instrument 510 about theinner axis parallel with the shaft length. Arrow J3 represents theflexing or bending of flexible shaft 528 at controlled flexible segment530. In this embodiment, flexible segment 530 is positioned directlyadjacent tool 534 at the distal end of shaft 528. Arrow J4 representsthe pivot action of a wrist joint, which links tool 534 to shaft 528,about axis 532. In this embodiment, tool 534 is exemplified as agrasper, and arrows J5 and J6 represent the opening and closing actionsof the tool jaws. Motions indicated by arrows J2-J6 are controlled fromcabling 524 originating at receiver 506.

FIG. 42A provides an enlarged perspective view of the distal end ofshaft 528 including flexible segment 530 and tool 534. Tool 534comprises upper grip or jaw 602 and lower grip or jaw 603, bothsupported from link 601. Base 600 is affixed to or integral withflexible shaft 528. Link 601 is rotatably connected to base 600 aboutaxis 532. A pivot pin may be provided for this connection. Upper andlower jaws 602 and 603 are rotatably connected to link 601 about axis536 and again, a pivot pin can provide this connection.

FIG. 42A shows eight cables at 538 extending through the hollow insideof shaft 528 for control of tool 534 and flexible segment 530. Two ofthese cables operate the bend of flexible segment 530, two cablesoperate one of the jaws 602, two cables operate the other of the jaws603 and the last two cables operate the wrist action about the axis 532.All of these cables travel through the hollow shaft 528 and throughappropriate holes in flexible segment 530, e.g. wire 525, as well asholes in base 600. Each of these pairs of cables operates in concert toopen and close jaws, pivot about the wrist, and bend flexible segment530.

One pair of cables travels through shaft 528 and through appropriateholes in the base 600, wrapping around a curved surface of the link 601and then attaching to the link. Tension on this pair of cables rotatesthe link 601 along with the upper and lower grips or jaws 602 and 603about axis 532.

Two other pairs of cables also extend through the shaft 528 and throughholes in the base and then pass between fixed posts 612. These postsconstrain the cables to pass substantially through axis 532, whichdefines rotation of link 601. This construction essentially allows freerotation of link 601 with minimal length changes in the cables passingto jaws 602 and 603. Thus, the cables actuating jaws 602 and 603 areessentially decoupled from the motion of link 601 and are not effectedby any rotation of link 601. Cables controlling jaw movement terminateon jaws 602 and 603. These cables permit independent operation of thejaws 602 and 603 in respective clockwise and counter clockwisedirections with respect to axis 536. A similar set of cables is presenton the under-side of the link 601 (not shown). Each of the jaws 602 and603, as well as the link 601, may be constructed of metal.Alternatively, link 601 may be constructed of a hard plastic material.Base 600 may also be constructed of a plastic material and may beintegral with shaft 528.

Bending of flexible segment 530 is provided via diametrically disposedslots 662, which define spaced ribs 664. Flexible segment 530 also has alongitudinally extending wall 665 through which cabling may extend,particularly for the operation of the tool. One of the pairs of cablesof bundle 538 controlling flexible segment 530 terminates where base 600intercouples with shaft 528. This pair of cables works in concert tocause bending as indicated by arrow J3, i.e. in a direction orthogonalto the pivoting provided at wrist axis 532. In FIG. 42A only one cable525 of two is illustrated.

FIG. 43 is an exploded prospective view showing carriage 508, receiver506 and drivable mechanism 526. Carriage 508 is adapted for motion alongrails 512 and 514. Pulleys 521 and 522 receive cabling, i.e. cablesections 513 and 515, which terminate at the carriage base at point 519.Other sections of this cable extend through an elongated hole or passagewithin carriage 508.

Receiver 506 and drivable mechanism 526 each comprise enclosed housingssupporting a plurality of control elements, such as intercouplabledrivewheels and associated pulleys or cams. Inter-engaging gears 540 and542 are supported respectively in the modules 506 and 526. A pair ofcables from bundle 524 engages pulley 544 (see FIG. 45) which, in turn,drives gear 540, and which further, in turn, drives gear 542 forproviding rotation of shaft 528. Collar 546 is provided at the terminusof the proximal end of shaft 528 for supporting shaft 528, which isdriven by gear 542. Cabling extending through collar 546 and shaft 528couple mechanical actions from drivable mechanism 526 through theflexible instrument shaft 528 to the distal end thereof.

Drivable mechanism 526 interlocks with receiver 506, providing themechanical connection that allows the drive unit to run cabling inflexible instrument 510. Blades 606, jutting out from the housing ofreceiver 506, engage with corresponding slots 608 associated withdrivable mechanism 526. Projecting from the proximal end of receiver 506is ridge 610, which is substantially U-shaped and provides anotherinterlocking feature for mating with a similarly shaped slot 614 at thesame end of drivable mechanism 526. Posts 616 protruding from thehousing of receiver 506 are adapted to releasably mate with holes 618 indrivable mechanism 526. Posts 616 and holes 618 to interlock with eachother, but may be released from each other via side-disposed buttons620, as illustrated in FIG. 46. FIG. 43 also shows the cam lockingscrews 615.

FIG. 44 is a partial broken away rear elevational view of interlockinginterfaces as seen along line 44-44 of FIG. 42. FIG. 44 shows alignmentposts 616 each having a groove 617, which is engaged by thecorresponding button 620. Button 620 is in the form of a plate memberbiased to a locked position by means of spring 621. A plate for button620 has a keyhole slot for receiving and holding post 616 therein.Button 620, however, may be manually depressed to release posts 616 andenable ready detachment of drivable mechanism 526 from receiver 506. Aretaining pin 625 may also be used to limit the travel of the buttonbetween in and out positions.

FIG. 45 is cross-sectional side view through the interconnecting modulestaken along line 45-45 of FIG. 42. FIG. 45 shows details of drive wheels(or pulleys) in the modules 506 and 526. Four drive wheels 622 aresupported within the housing of receiver 506. Drive wheels 622 receivecabling for controlling the motions of the shaft and the tool, where thecable protrudes from cable bundle 524 in FIG. 43. Each of these pairs ofcables is controlled from a corresponding motor, which is part of thedrive unit (see discussion of FIG. 49, below).

FIG. 45 also shows output blades 606, previously shown in FIG. 43, whichextend into corresponding slots 608. These slots are disposed inrespective intergaging drive wheels 624 of the drivable mechanism 526.Blades 606 have a rectangular end construction for engaging with similarrectangular slots 608 associated with the module 526. FIG. 45 also showsthe gears 540 and 542 in engagement to allow drive to occur from bundle524.

FIGS. 45 and 46 show a series of idler cams 626, one associated witheach of drive wheels 624. FIG. 46 is a plan cross-sectional plan viewthrough receiver 506 as taken along line 46-46 of FIG. 45. FIG. 46 showsthe placement of cams 626. A cable wraps around each of drive wheels 624and is held in position by its associated cam 626. FIG. 46 also showsall of the cables running parallel to each other at region 627, wherethe cables run from respective drive wheels 624, through collar 546 andextending down inside shaft 528 to the distal end. With the use of theplacement and adjustment of cam 626, the cables are all directed in amanner to easily couple into shaft 528.

Each of cams 626 has an off-center axis 631. As viewed in FIG. 46, cam626 may be rotated clockwise to tighten its associated cable. Rotationcounterclockwise loosens the tension. Cam locking screws 615 secure cam626 in an adjusted-to position (see FIG. 48, a cross-sectional viewtaken along line 48-48 of FIG. 47). FIG. 48A is a cross-sectional viewtaken along line 48A-48A of FIG. 48. As depicted in FIGS. 46 and 48A,the cable associated with each wheel 624 may be secured in a cableclamping hole 633 via a cable clamping screw 635. A similar clampingarrangement is associated with wheels 622. A roll pin fixes each wheel622 to each spindle 607.

FIG. 47 is a cross sectional plan view taken through receiver 506, astaken along line 4747 of FIG. 45. The cross-sectional view of FIG. 47illustrates drive wheels 622 associated with receiver 506. Drive wheels622 receive cabling from cable bundle 524. Each of a pair of idlerpulleys 630 are associated with drive wheels 622. At the very input toreceiver 506, idler pulleys 632 are used for directing the cable toidler pulleys 630 and from there to drive wheels 622.

FIG. 48B is a fragmentary plan view of a drive wheel engagement slot byitself as seen along line 48B-48B of FIG. 48A. The cross-sectional viewsof FIGS. 48A and 48B illustrate drive wheels 622 within receiver 506having associated end blades 606. End blade 606 is a screwdriver-typeblade that engages a slot previously identified as slot 608 in FIG. 43.This slot 608 is in drive wheel 624 of receiver 526. In FIG. 48B, slot608 displays a tapered portion. The tapered portion allows easyregistration of end blade 606 and slot 608, and thus easy registrationbetween drive wheel 622 and drive wheel 624.

As described to this point, the bending or deflection of the shaft canbe actuated by mechanical means such as a wire extending along a lengthof the shaft. Thus, actions at the distal end of shafts may becontrolled by mechanical elements, such as cables, wires or othertendons.

Alternatively, actuation of the controlled bending can occur by othermeans, such as by remote electromagnetic signal couplings. FIG. 41Aillustrates shaft 850 having a central lumen. Residing in the centrallumen is an operative or controlled flexible segment O, in the form of aplurality of spaced electromagnetic rings 852, separately labeled as R1,R2, R3 and R4. Each of rings R1-R4 is associated with wires 854,similarly labeled as wires W1, W2, W3 and W4. Rings 852, once energized,provide bending of shaft 850 at flexible segment O. FIGS. 41A and 41Dare meant to be schematic, while FIGS. 41B and 41C are actualimplementations for actuation of the rings by means of coils or windings853. As illustrated in FIG. 41B, each ring may be electrically energizedvia a winding 853 associated therewith. FIG. 41B shows a fully woundwinding, while FIG. 41C shows a half wound winding. Ring 852 may alsohave two separate half wound coils on opposite sides thereof. Wires 854(in pairs) are selectively energized to energize windings 853 on therings, which in turn, provide either attraction or repulsion of therings. FIG. 41D illustrates the results of regions of rings 852 beingenergized to attract or repel adjacent rings. For example, a certaindirection of current flow through windings 853 can create an attractionof the coils at the bottom and a repulsion of coils at the top. Thiscooperative action causes a bending at the operative or controlledflexible segment O.

The flexible instrument depicted in FIGS. 6 and 7 provides only thedistal end as being remotely controlled. It can readily be appreciatedthat a controlled flexible segment may be provided, not necessarily foraction at a target site, but to control certain movements of thecatheter to assist in reaching a target site.

FIGS. 4 and 5 illustrate the advantages of a flexible instrument,particularly a catheter having controlled flexibility via controlledflexible or operative segments, for use in performing a procedure or forguiding the instrument through a natural body lumen. FIG. 4 provides aschematic cross-sectional diagram, illustrating a catheter K for use inmitral valve repair, to be discussed in more detail below. FIG. 4 alsoshows catheter K supporting a tool 18 for carrying out certainprocedures at the mitral valve annulus, also described in further detailbelow. In FIG. 4, catheter K is shown entering the femoral vein V by apercutaneous access at S. From the femoral vein V, catheter K must bendprior to entering the right atrium R. Catheter K then passes through aseptal wall of the heart to the left atrium L, which is directly abovethe mitral valve M. In this particular embodiment, the operative segmentof the catheter K is illustrated at O and is positioned near the verydistal end of the catheter K. Thus, at the sharp, almost 90.degree. bendprior to entering right atrium R, a user can controllably bend catheterK at the operative segment, to perform a procedure with tool 18. Also,the ability to controllably bend catheter K prevents tool 18 fromconceivably being trapped within femoral vein V, causing damage to thewalls of vein V. In this embodiment, it may be preferable to have atleast some length of catheter K constructed of a deformable or flexiblematerial, enabling the catheter to easily pass through the body lumen byessentially conforming to vein configurations, such as that of femoralvein V.

FIG. 5 provides a schematic cross-sectional diagram illustrating asurgical procedure where catheter K1 enters a natural body orifice, suchas the urethra for carrying out procedures in, for example, the bladder.In FIG. 5 catheter K1 is shown extending into bladder B1. In thisexample, the computer controlled segment, identified as operative orflexible segment O in FIG. 5, is positioned at a more proximal sectionof catheter K1. Bladder B1, being an open cavity, does not have lumensleading from the urethra that would naturally guide a catheter towardsany particular operative site. Upon entering bladder B1, catheter K1 canbend in any direction and not necessarily in the direction of theoperative site. In this embodiment, because of the more proximalpositioning of operative segment O, a surgeon can controllably bend thedistal end of catheter K towards the operative site. In the embodimentshown in FIG. 5, the distal end of the catheter, labeled P1, can berigid or be “passively” flexible, i.e. made of a flexible material andnot necessarily controlled for flexure under remote computer control.

In the illustration of FIG. 4, the catheter K may be fed through thefemoral vein by direct surgeon manipulation, in which case only theoperative segment O is under computer control from a master station.Alternatively, the catheter may translate linearly through the veinunder remote master station control, where the catheter can have otheroperative segments disposed at different locations of catheter K. Eachof these operative segments can be controlled from a master station forassistance in the guiding of the catheter to a predetermined targetsite. Thus, the catheter may be inserted manually and also have remotecomputer control for at least limited linear translation.

FIGS. 3A-3C show different embodiments of flexible instruments withmultiple operative or controllable flexible segments. Shafts havingmultiple operative segments can be very useful for procedures in a bodycavity, as discussed previously, but can also be useful in navigatingthe shaft through intricate or delicate body lumens. FIGS. 3A-3Cschematically illustrate controller CT and a slave portion of the systemcomprising actuators or drive units A1-A4 and shaft KA, KB or KC havingthree operative segments O1-O3. In accordance with each of theseembodiments, a surgeon inputs commands from a master station to causecertain corresponding movements of the shaft at the slave station. Asurgeon's manipulations at the master station are coupled to controllerCT where these manipulations are mapped to actions at operative segmentsO1-O3. Thus, a surgeon, at an appropriate input device, may carry out afirst manipulation to control a segment O1, a second differentmanipulation to control the segment O2 and still a third manipulation tocontrol the segment O3, either simultaneously or sequentially. A fourthmanipulation may control the tool G.

FIG. 3A shows shaft KA having three operative segments, O1, O2, and O3,and tool G at its distal end. Actuators A1, A2 and A3 are associatedrespectively with operative segments O1, O2 and O3. Actuator A4 controlstool G. Each of actuators O1-O3 is controlled from controller CT.Operative segments O1, O2 and O3 are spaced a certain distance apartfrom each other, allowing shaft KA to simultaneously experiencecontrolled bends. This arrangement may be necessary for lumens withmultiple bends, or for hard to reach operative sites.

FIG. 3B, shows catheter KB having tool G1. In this embodiment, threeoperative segments O1, O2 and O3 are spaced from each other along thelength of catheter KB. Segments O1-O3 can be controllably bent to forman arc having an imaginary radius point P. Thus, this arrangement ofoperative segments can actuate particularly acute bends. In anotherembodiment, catheter KC in FIG. 3C employs three operative segmentsO1-O3, which are contiguous. The radius of curvature can be increased.

It is understood that non-operative segments of the catheter in FIGS.3A-3C can comprise either a flexible or a rigid material. It can beappreciated that one or more controlled flexible segments can beincorporated in the shaft, depending on the particular application.

Another aspect of the present invention provides a remote controlledflexible instrument operable within the sterile field, and disposableafter use. The sterility of reusable medical instruments and implementsare maintained by well-known methods such as exposure to sterilesolutions and/or autoclaving. For some medical implements, it can bemore cost effective to manufacture them from low cost materials anddispose them after a single use, or use on a single patient. But forcertain other medical instruments, its manufacture from low costmaterials still results in a costly product due to the intricate natureof the individual parts and the labor required to manufacture complexcomponents.

It is another feature of the present invention to provide a design for aremote controlled flexible instrument having disposable components,particularly those components that are exposed to the sterile field. Thepresent design allows the use of injection-molded plastic parts. Thedisposable component can be easily and quickly engaged into anddisengaged from a non-disposable, reusable base. The components can belocked onto the base by snapping or interlocking matched parts, withouthaving to thread cable wires or attach any intricate components.

One aspect of the present invention provides a disposable implementcomprising a disposable mechanically drivable mechanism, a disposableshaft extending from the drivable mechanism, and optionally a disposabletool supported on a distal end of the shaft. Referring back to FIG. 7,mechanically drivable mechanism 26 comprising gears 60 and 68 andpulleys 64 and 72, can be manufactured from injection molded plastic, aswell as shaft 30 extending from drivable mechanism 26. The sides ofpulleys 64 and 72 feature a first semicircular planar disc stepped upfrom a second matching semicircular planar disc. The sides of thepulleys in receiver base 24 correspondingly match the stepped up patternof pulleys 64 and 72. Engaging drivable mechanism 26 onto receiver 24requires matching and interlocking the respective pulley discs. Thus,the interlocking feature in effect extends the cabling pathway from thefirst set of cables running from the drive unit to receiver 24, to asecond separate set of disposable cables contained within drivablemechanism 26 and shaft 30. No tying or threading of cables is requiredto engage the disposable portion onto receiver 24.

Another design for a disposable implement is illustrated in FIG. 42. InFIG. 42, the flexible instrument 510, comprising drive mechanism 526 andshaft 528, can be a single piece disposable unit that is readilyengageable and disengageable relative to the base module 506.

Disposable implement 510 may be considered as comprising a disposable,mechanically drivable mechanism such as the coupler or module 526interconnected to a tool 534 through an elongated disposable flexibleshaft or stem 528. This disposable and flexible implement is mounted sothat the mechanically drivable mechanism may be connectable to anddrivable from a drive mechanism, such as illustrated in FIGS. 6 and 7.In the illustrated embodiment the drive mechanism may be considered asincluding the coupler or module 506 and the associated drive motors. Thedisposable elongated flexible instrument is generally inserted into abody vessel or cavity of a subject along a selected length of thedisposable elongated instrument with the elongated flexible instrumentbeing disposable together with the disposable mechanically drivablemechanism.

The disposable implement is purely mechanical and can be constructedrelatively inexpensively thus lending itself readily to beingdisposable. It may be difficult to make only the tool disposable, due tothe intricate nature of the tool parts, which may require the user toperform intricate maneuvers and cable threading into the base of theslave station. Here, the disposable implement, i.e. the tool, shaft anddrivable mechanism are manufactured as a single piece disposable unit,thus eliminating the need for intricate instrument or tool exchangeprocedures.

Ideally, the base of the slave station, which contacts the disposableimplement, is easily cleanable. It is preferred that the disposableimplement, which operates within the sterile field, experiences minimalcontamination by contacting the slave station. In one embodiment of thepresent invention, as illustrated in FIG. 43, the interlocking drivablemechanism 526 and receiver 506 features substantially planar surface atthe point of contact between the two modules. Regarding receiver 506,the planar surface is easy to clean and the inner intricate pulleys andcabling are protected from contamination by the housing. Regardingmechanically drivable mechanism 526, the housing can be made ofinjection-molded plastic that is simple to manufacture and is easilydisposable.

One advantage of the present invention is the ease of engaging anddisengaging the disposable implement. In a particular medical procedure,a multitude of instrument exchanges may be required, and the system ofthe present invention is readily adapted for quick and easy instrumentexchange. Because the receiver is maintained in a fixed position, thesurgeon can easily exchange instruments by readily decoupling at themodules 506 and 526. The ease of exchanging instruments lends to theportability of the slave station. This portable nature of the slave unitcomes about by virtue of providing a relatively simple flexibleinstrument in combination with an adaptor (module 506, module 520,carriage 508 and associated components) for supporting the flexibleinstrument. Overall, the slave station is of a relatively smallconfiguration. Because the slave unit is purely mechanical, and isdecouplable from the drive unit, the operator can readily position theslave unit. Once in position, the slave unit is then secured to thesupport, and the mechanical cabling of the slave unit is then attachableto the drive unit. This makes the slave unit both portable and easy toposition in place for use.

FIG. 49 shows an embodiment where pulley 677 is readily manuallydecouplable from motor 675. For this purpose pulley 677 may be atwo-piece pulley arrangement comprising a coupler spindle and a couplerdisk with the coupler disk secured to the output shaft of the motor.

This enables the entire assembly to be disconnected at the motor so thatthe flexible instrument system 500 with its flexible instrument 510 maybe positioned relative to the patient, independent of any coupling withthe drive motors. Once the system illustrated in FIG. 42 is in place,then the coupling of the cables can be made at pulley 677 to providedrive to the flexible instrument system.

Another aspect of the present invention provides a system for repairinga cardiac valve, such as a mitral valve. Current mitral valve repairtechniques, either open or minimal access, require the surgeon to placethe patient on cardiopulmonary bypass and stop the heart. The leftatrium is then opened and exsanguinated to allow the surgeon to performthe repair. This aspect of the present invention provides a minimallyinvasive mitral valve annuloplasty technique featuring the followingadvantages: (1) peripheral venous access; (2) the heart can continue tobeat during the repair; and (3) assessment of the correction of valveincompetence in real-time using, for example, Doppler ultrasoundguidance.

In one embodiment, the present cardiac valve repair system employs aguide shaft extending from a site outside a patient to an area about thecardiac valve. The guide shaft receives a flexible inner shaft fordisposing a tool at the area about the cardiac valve, where the tool issupported at the distal end of the guide shaft. Preferably, the innershaft has a relatively small diameter enabling percutaneousintravascular and endoscopic surgery. Even more preferably, the innershaft, and optionally the guide shaft, is capable of accessing themitral valve from the peripheral circulation, eliminating the need forincisions through the chest wall. In one embodiment, the inner shaft canhave a diameter ranging from 8 to 15 French (2.5-5.0 mm). The outercatheter may be constructed from a standard 9 French coronary guidecatheter, having a diameter of 2.67 mm and a wall thickness of 0.1 mm.In other embodiments, the inner catheter can have an outer diameter of1.1 mm and an inner diameter of 0.09 mm. In yet another embodiment, thebraided stainless steel cables are 0.63 mm in diameter and are capableof transmitting 178 Newtons (40 lbs. approx.).

A feature of this aspect of the present invention is that thepercutaneous access to the mitral valve can be accomplished on a beatingheart, eliminating the risks associated with cardiopulmonary bypass(CPB). To enable a procedure on the beating heart, preferably theprocedure can be performed under physiologic conditions. The physicianmay monitor the procedure by, for example, transesophagealechocardiography, instead of a video image. This technique enablesreal-time assessment of the correction of the mitral valve regurgitation(MR) during the procedure, further enabling intra-operative provocativecardiac testing, with preload and afterload challenges and cardiacpacing all under trans-esophageal echo and trans-thoracic ultrasoundguidance to optimize repair.

The tool can be remote controlled, as described herein, and can bedesigned for use in any procedure of the cardiac valve repair process.For example, a first set of tools is capable of percutaneous mitralvalve annuloplasty. This represents a paradigm shift in management ofdisease from MIS and open surgical to intraluminal interventions. Whilethis catheter-based intervention is described in connection with mitralannuloplasty, the technique can also be applied to other structures suchas, by way of example and not limiting, the billiary tree, thegenitourinary tract and intraventricular neurosurgery.

The system further includes a retainer at the area of the cardiac valve,where the retainer is attached to an annulus of the cardiac valve. Aswill be described in greater detail below, the retainer is closeable viathe tool to draw the annulus into a smaller diameter.

In one embodiment, a trans-septal guide catheter is used to guide andsupport an inner catheter. The guide catheter is introduced bypercutaneous access, and allows the clinician to access the left atriumvia the venous circulation, i.e. through the heart wall (see FIG. 4).The guide catheter may be non-robotic, i.e. simply manipulated manuallyby the surgeon.

Alternatively, the guide catheter may be robotically controlled fromsurgeon manipulations at an input device of the master station.

Once access to the left atrium is established, the inner catheter isthreaded into the left atrium through the guide catheter. The innercatheter contains attachment anchors for deployment at desired pointsaround the mitral valve annulus. A remote controlled 5-degree-of-freedomtool and wrist can be utilized to precisely reach the annulus.Ultrasound may be used to visualize the system and guide the anchorpositioning and placement. This ultrasound may be trans-esophagealultrasound or trans-thoracic ultrasound, for example. Furthermore,electrophysiologic signals of the heart may be used to aid in preciselylocating the position of the tool at the fibrous mitral valve annulus.

There is now described a number of techniques employing the catheterapparatus of the present invention. These techniques are describedherein primarily in connection with mitral valve repair.

FIG. 19 is a schematic representation of the heart muscle showing theleft ventricle 218, the right ventricle 219, the left atrium 220, theright atrium 221 and the aorta 222. Between the left atrium and the leftventricle, blood flow is from the left atrium through the mitral valve210 to the left ventricle 218. FIG. 26 illustrates an expanded view of amitral valve at 210 including annulus 211 and leaflets 213. FIG. 27illustrates schematically the leaflets 213 of the mitral valve 210 withthe mitral valve annulus 211. As a heart muscle ages, it is typical forthe annulus of the mitral valve 210, illustrated in FIG. 19 at 211, toexpand in diameter causing problems with the leaflets 213. If theleaflets fail to close properly, regurgitation may result, causingleakage by the mitral valve in the reverse direction and resulting inimproper blood flow through the heart. Thus, mitral valve repairinvolves, at least in part, shrinking the diameter of the annulus toallow the leaflets to operate properly.

In one embodiment, threading or sewing a ring about the annulus reducesthe annulus diameter, where the ring is closeable. The annulus comprisesrelatively tough tissue just above the top of leaflets. As viewed inFIG. 19, the opposite end of the annulus at 217 tends to expandoutwardly. FIG. 19 illustrates an area at the annulus of the mitralvalve (that annulus being at the top in FIG. 19) identified as trigonearea 215, where the valve ring is more rigid and remains stationary.Because this area is relatively stable and rigid, it is thus difficultto contract, and most of the expansion of diameter of the ring occursaway from the trigone area. This, again, is illustrated in FIG. 20 bythe positions shown in solid and in dotted outline.

FIG. 20 shows schematically parts of the heart such as the left atrium220 and the left ventricle 218, with the mitral valve 210 disposedtherebetween. FIG. 20 illustrates the annulus of the mitral valve insolid position, at a smaller diameter where the leaflets operateproperly. The dotted outline 217 represents the expanded diameter of thebase of the mitral valve, the state at which mitral valve leakage canoccur.

To carry out the technique of the present invention, a guide catheter230 is employed, such as a transseptal atrial guide catheter. The accessfor catheter 230 is via the vena cava to the right atrium 221. Thisaccess may be from above via the jugular vein or below by way of thefemoral vein. A puncture is made in the wall 238 of the right atriuminto the left atrium 220, allowing distal end 232 of catheter 230 topass into the left atrium 220.

FIG. 17 illustrates one method of shrinking the diameter of the annulus.FIG. 17 shows a metal wire ring 100 in place about the mitral valveannulus. The ring 100 may be initially secured at the trigone area 103of the mitral valve annulus. The technique illustrated in FIG. 17 mayrely upon a catheter apparatus, such as depicted in FIGS. 6 and 7 hereinwith an operative segment. At least limited linear translation of thecatheter may be accomplished with an apparatus similar to that describedin FIG. 6, although a guide catheter may also be manually inserted atleast partially by the surgeon through percutaneous access via thefemoral vein. The ring 100, although depicted in a ring configuration inFIG. 17, can be first inserted through the catheter in a straightenedconfiguration. The metal wire or ring 100 is preferably constructed of amaterial such as Nitinol. The characteristics of this material includethe ability to retain its form or to be stretched to a straightposition. Once the material is passed through the catheter, it canspring back to its ring configuration. The surgeon preferably matchesthe configuration of the ring, particularly as to its size, to provide aproper fit for the particular mitral valve that is being repaired.

Once the straightened wire 100 has passed through the catheter, itassumes the position shown in FIG. 17. The ring, once in place, issecured to the annulus via wire clips 106 and/or sutures 102. By drawingon these sutures with the tool, the diameter of the mitral valve annulusis reduced so that it conforms to the size of the wire loop 100. As withother techniques described herein, the control is supplemented by visualconsiderations such as with the use of ultrasound orelectrophysiological feedback.

FIG. 18 provides another embodiment of the present invention employing acatheter system for mitral valve repair. FIG. 18 provides a schematicrepresentation of a ring 210 of a cardiac valve, such as a mitral valve.Fiber 212 is looped about or sewn around the annulus (base) of thevalve. A number of different types of stitches may be used. The fibermay be a thread or a wire. In the embodiment of FIG. 18, the fiber isactually sewn through the annulus of the valve. After the fiber is sewnin this manner, tension is applied to ends 214 of the fiber. Thetightening reduces the diameter of the ring, brings the valve leafletsinto their proper position so as to avoid valve regurgitation.

FIG. 20 also illustrates a balloon 234 that may be supported at thedistal end 232 of the catheter 230. Once the catheter 230 is in place,balloon 234 is inflated to further support the guide catheter in placewith the end 232 extending slightly into left atrium 220. Once balloon234 is inflated or opened, it can be snugged back against the septalwall 238 between left atrium 220 and right atrium 221. The innerdiameter of the catheter 230 may be on the order of approximately 5 mmin diameter. FIG. 24 shows an enlarged view of catheter 230, with itsend 232 and the associated balloon 234 holding catheter 230 in place.

As an alternate to the use of a balloon 234, a malecot 236 may be used.This is a mechanical device with expandable wings, as illustrated inFIG. 25 and associated with catheter 230 so as to hold the end 232 ofthe catheter in place relative to the septal wall 238.

FIG. 20 also illustrates a flexible catheter 240 with its associatedtool 242 extending from the guide catheter 230. Tool 242 may be a pairof jaws operable for threading or sewing fiber. These jaws can becontrolled externally at a user interface by a surgeon. With regard toflexible catheter 240, reference is made to co-pending provisionalapplication, U.S. Ser. No. 60/269,200, as well as pending applicationPCT serial number PCT/US00/12553, filed Nov. 16, 2000, both documents ofwhich are hereby incorporated by reference herein.

In FIG. 23 reference is also made to the fiber 212 and an end piece 245that is secured to one end of the fiber 212. Fiber 212 is shown sewnthrough wall 247. FIG. 23 also schematically illustrates the tool 242engaging the fiber 212.

After guide catheter 230 is in place with the balloon 234 inflated tosecure it in position, flexible catheter 240 is threaded through guidecatheter 230 to a position just about the mitral valve, as illustratedin FIG. 20. Fiber 212 may also, at the same time, be threaded throughthe catheter member 230 with end piece 245 being accessible for beingsecured to the valve ring. As illustrated in FIG. 20, the beginningposition of the threading or sewing of the fiber 212 is at a positionclose to or at the trigone area 215 of mitral valve 210.

After a single threading or sewing has occurred, such as in FIG. 23,then the jaws of tool 242 loop stitch the fiber 212, which may be asmall but rigid wire, about the mitral valve in the manner illustratedin FIG. 18. Staples 249 may also be employed for holding the wire inplace.

FIGS. 21 and 22 illustrate another embodiment to secure an end of fiber212. In this embodiment, the end of fiber 212 is pulled so as to closethe diameter of the base ring of the mitral valve. FIG. 21 illustratesguide catheter member 230 at its end 232, being held in place againstthe septal wall 238 by balloon 234. Flexible catheter 240 with its tool242 has been withdrawn from catheter member 230. Double-walled structure250 comprises coaxially arranged inner and outer tubes 252 and 254.Fiber 212 extends through these tubes and carries therealong a securingpiece 256 and a retaining button 258. The inner tube 252 is adapted toengage the retaining button 258 and the outer tube 254 is adapted toengage the securing piece 256. FIG. 22 shows securing piece 256 andretaining button 258, along with the fiber 212.

Initially, once the threading through the base of the valve ring iscompleted, the outer tube 254 engages securing piece 256 moving itdownwardly in the view of FIG. 21 while the fiber 212 is held inposition. This tightens the securing piece 256 against the other side ofthe trigone area 215, of FIG. 20. Once the diameter of the ring has beentightened, inner tube 252 is moved downwardly to engage retaining button258. Button 258 grabs fiber or wire 212 and at the same time retainingbutton 258 engages and interlocks with the securing piece 256. In thisway, both ends of the threaded fiber or wire 212 are secured roughly atthe positions illustrated in FIG. 20. The pulled fiber 212 causes themitral valve ring to draw into a smaller diameter such as the positionshown in solid, rather than the in-dotted position of FIG. 20.

Once the securing piece and the retaining button are firmly held to thewire 212, then the member 250 may be withdrawn through the guidecatheter 230. The flexible catheter member 240 may then be reinsertedwith a different tool such as a pair of scissors for cutting the exposedend of the fiber 212.

Another possible technique for reducing the annular diameter involves aloop of cable that extends through hooks or anchors placed in theannulus, as illustrated in FIG. 29. FIG. 29 shows the cable or wire 120and schematically illustrates the anchors at 125. In this technique thevalve is reduced through a “lasso” technique, in which the cable exertsan equal force on all of the anchors. This technique uses an articulatecatheter preferably inserted through a guide catheter, such asillustrated hereinbefore, to place the anchors one at a time into themitral valve annulus. The cable onto which the anchors are suspendedprovides the closing force when tensioned by the operator.

In one embodiment, the flexible instrument comprises a guide catheter150, as illustrated in the diagram of FIG. 30. Inner catheter 155 housesan anchor and cable system depicted generally at 160, includingtensioning cable 162 and anchors 164. Five degrees-of-freedom areprovided: (1) rotary, (2) linear, (3) flexure motion with regard to theguide catheter 150 as well as (4) linear and (5) rotary motion withregard to the inner catheter 155.

Guide catheter 150 may be approximately 8 French in diameter with acomputer controlled flexible end portion, illustrated in FIG. 30 asoperative segment O. A computer controls three degrees-of-freedom withregard to the guide catheter 150, along with two degrees-of-freedom ofinner catheter 155. Refer to FIG. 30 and the corresponding motionsF1-F5.

FIG. 30 depicts anchors 164 as having a loop and two legs, althoughother anchor designs can be readily contemplated. The legs of eachanchor 164 may curl outwards. Once anchors 164 are deployed from theconstraint of the inner catheter, they curl outwardly. The curlingmotion of the anchor legs secures them to the fibrous tissue of themitral valve annulus. Preferably the anchors are fabricated from asuper-elastic material such as Nitinol.

A tensioning cable, such as the cable or wire 162 illustrated in FIG. 30may pass through each of the loops of the anchor. This allows an equalforce to be placed on each anchor and prevents the anchors from becomingloose in the bloodstream. The tensioning cable passes back through therobot inner catheter and out of the patient. The final tension isadjusted manually by the surgeon (or by computer) to optimize theannular size under direct visualization. Also, within the inner catheteris preferably disposed a deployment wire used to advance and fire theanchors into the annulus wall.

FIGS. 30A and 30B depict a cable termination tool set. This setcomprises two catheters used to: (1) crimp the end of the tether cableonce the tension is placed on the annulus; and (2) cut off the remainingcable at the end of the procedure. Both of these catheters may use afour-bar linkage or other system.

FIG. 30A shows a crimp tool 172 having a pair of jaws 174 that can beused to crimp member 176 about the tether cable 170. Thus, the firstcatheter 172, which may be referred to as a cable crimper, holds thecrimp element 176 in the jaws 174 with the tether cable 170 pre-threadedthrough the crimp element and catheter shaft. The tensioning of thecable may be performed under ultrasound guidance. Although one tethercable 170 is shown in FIG. 30A, opposite ends of the tether that comefrom the mitral valve site preferably extend through the crimp element176. Once the tether cable is tensioned, so as to bring the mitral valveinto its proper diameter, then the crimp element 176 is actuated by thecable crimper 172 illustrated in FIG. 30A. Once the proper tension isachieved, the crimper is actuated by applying tension on the push-pulldrive cable 175 and by closing the crimp element at the jaws 174 so thatthe crimp element crimps the tether cable 170 in the proper position andat the proper tension.

After the crimping or securing step, then the cable crimper is removedand the cutting catheter 182 is introduced as also illustrated in FIG.30B. This catheter is also introduced over the tether cable 170 andthrough the guide catheter. It is advanced up to the crimp, and seversthe cable with its jaws 184 by tensioning the push-pull drive cable 185.The procedure is now completed and the system catheters are thenremoved.

As indicated previously, the proximal end of the catheter is comprisedof a disposable coupling mechanism that engages a drive mechanism, suchas is shown in FIGS. 6 and 7. For this purpose, the coupler, identifiedin FIGS. 6 and 7 as couplers 24 and 26 are adapted for disengagementtherebetween. One coupler section may be considered as transmittingmotion to the guide catheter while the other coupler section may beconsidered as transmitting motion to the inner catheter and the drivecable. This involves the mechanical coupling of the guide catheter withthe coupler so that actions of the guide catheter are controllable fromthe mechanical control elements of the coupler.

In one embodiment, a drive unit is coupled with the inner shaft and theguide shaft independently, the drive unit capable of independentlyeffecting movement of each shaft to at least one degree of freedom.

For each coupler element, rotary disks transmit motion from the remotelycontrolled drive system to the catheter articulations. By way ofexample, in a first coupler element, a horizontal disk may drive thedistal flexure. Another element may include disks, which control theaxial and/or rotary positions of the inner catheter and, for example,the advance of the anchors. All of the coupling elements are mounted ona slider or sliders, which allows independent control of the linearadvance of the outer and inner catheters. Again, refer to FIGS. 6 and 7.The catheter system including the inner and outer portions, as well asthe proximal coupling element are disposable and mount removably to thedrive member.

In accordance with the technique, such as described in FIG. 29, when thelast anchor is in place, the inner robot catheter and deployment wireare removed. The physician can manually (or under computer control)adjust the tension in the cable and thus the diameter of the mitralvalve after the first element of the cable termination system isthreaded over the cable and through the robot guide catheter. Since thisprocedure is performed on a beating heart, the annular size can beoptimized under direct ultrasound guidance. Once the mitral valveannulus has been precisely adjusted, a cable termination system, such asthe one depicted in FIGS. 30A and 30B, clamps and cuts the cable. Thiscompletes the mitral valve repair procedure.

Another feature of the present invention provides a system for closingthe base of a cardiac valve, such as a mitral valve. The closing canoccur primarily by a stapling technique in which staples are attached tothe valve ring or annulus to draw the annulus into a smaller diameter.In this way the leaflets are then more appropriately positioned foropening and closing.

FIG. 31 illustrates a staple array comprising delivery system 342including storage housing 349 for a plurality of staples 350. Each ofstaples 350 is a surgical staple movably mounted within housing 349.Cable or wire 312 interconnects and loops through each of staples 350.Each staple 350 includes a pair of pointed ends 351 and center loop 353.The staple 350 at the most distal end of housing 351 (i.e. nearest theexit of housing 351) has cable 312 attached fixedly at loop 353, toprevent losing staples in the subject. For the remaining staples, cableor wire 312 freely loops through center loop 353. A release mechanism,not illustrated in FIG. 31, but which may be a standard design, can beused to move staples 350, one at a time, out of the housing 349. FIG. 31also schematically illustrates a clamping mechanism 352 at the distalend of housing 349, for closing each of staples 350 as they exit housing349.

FIG. 32 illustrates another method for repairing a mitral valve,featuring the use of staples to secure a ring to the mitral valveannulus. As will be described in further detail, a tether cable orfilament is threaded through an array of staples or anchors via a firstinner catheter. Once the attachment anchors are placed around theannulus, the first inner catheter is removed and a second inner catheteris disposed in the guide catheter. This second inner catheter allows theclinician to apply tension to the cable to reduce the mitral valveannulus circumference, in effect, pulling on a lasso. The annuloplastyis monitored by real-time echocardiographic quantitation of regurgitantflow attenuation, with and without after-load reduction. The clinicianmonitors the cardiac physiology for resolution of regurgitation. Whenthe hemodynamics are optimized, still a further inner catheter devicemay be used so as to place a stop or crimp on the cable. Still anotherinner catheter device may be used to cut the cable. These latter twoinner catheter devices may be robotic or non-robotic catheters.

FIG. 32 features mitral valve 210 with trigone area 215. Guide catheter330 accesses the vena cava and passes to the right atrium 221. Thisaccess may be from above via the jugular vein or below by way of thefemoral vein. A puncture is made in septal wall 238 separating rightatrium 221 from left atrium 220, allowing distal end 332 of guidecatheter 330 to access left atrium 220.

Balloon 334 may be supported at distal end 332 of guide catheter 330.Once guide catheter 330 is positioned at a desired location, balloon 334is inflated to secure guide catheter 330 to the wall with end 332extending into the left atrium. Once balloon 334 is inflated, it can besnugged back against the septal wall between left atrium 220 and rightatrium 221. The inner diameter of the catheter 330 may be on the orderof approximately 5 mm in diameter. As an alternative to balloon 334, amalecot may be used, i.e. a mechanical device having expandable wingscapable of securing catheter 330 against septal wall 238.

Guide catheter 330 coaxially nests flexible catheter 340 and itsassociated staple delivery system 342. With regard to this catheterconstruction, reference is made to a co-pending provisional applicationSer. No. 60/269,200 filed Feb. 15, 2001, as well as pending applicationPCT serial number PCT/US00/12553, filed Nov. 16, 2000, both of which areincorporated by reference herein in their entirety.

After balloon 334 is inflated to secure guide catheter 330 in position,flexible inner catheter 340 is threaded through guide catheter 330 to aposition just above mitral valve 210, as illustrated in FIG. 32.Delivery system 342, associated with inner catheter 340, also passesthrough catheter 330, holding fiber 312 and staples 350 to an area aboutthe mitral valve.

FIG. 32 also illustrates fiber 312 tracing a circumference about annulus211, terminating at two end locations 345 and 356. The area traced byfiber 312 and where the stapling occurs is at a ring of relatively toughtissue just above the top of leaflet 213. The area not traced by fiber312 is valve trigone area 215, which is relatively fixed and not easilycontracted. Thus, the repair of the mitral valve, involving decreasingdiameter 217 from dotted line to solid line, occurs away from trigonearea 215.

Flexible catheter 340 is manipulated to cause a stapling about annulus211 of mitral valve 210. The releasing of each staple is controlled by amechanism preferably within flexible catheter 340 and operable from auser interface station remote from the subject. Once all of the staplinghas occurred, wire 312 is pulled in the direction of arrow 361 in FIG.32. This pulling causes a closure of valve annulus 211, as desired. Oncethe clinician is satisfied that the repair is complete, the cable 312 isthen locked off with a crimp, such as illustrated at 365 in FIG. 33.This crimp may be facilitated by the insertion of a different cathetermember 340 within the catheter 330, all while the cable 312 is held inthe proper cinched-down position.

A plurality of staples 350 having loops 353 encircling fiber 312,secures fiber 312 to the annulus of the mitral valve, terminating atpoints 345 and 356. The procedure of looping fiber 312 and stapling canbe performed via remote control from a master station under surgeoncontrol with multiple degrees-of-freedom of the tool so as to accuratelylocate the implant fiber 312 and staples 350.

Fiber 312 is fixedly secured to end staple 350 at point 345. Theremaining staples are free to glide along fiber 312. When all thestaples are secured about the annulus, fiber 312 may be cinched downunder ultrasonic guidance, watching for a reduction or elimination ofthe valve regurgitation. Once adequate tension has been placed on thecable 312, tension can be maintained without disengaging the closuresystem. This allows the clinician to monitor the patient for some periodof time to confirm that the repair has taken place. Once the clinicianis satisfied with the repair, the cable can be locked off with a crimpor by some other technique and the cable may then be cut.

Another feature of the present invention is that the technique can beperformed under physiologic conditions. The physician can monitor theprocedure by, for example, transesophageal echocardiography, instead ofa video image. The aforementioned “lasso” technique enables real-timeassessment of the correction of the mitral valve regurgitation (MR) asthe “lasso” is tightened. This enables performance of intra-operativeprovocative cardiac testing, with preload and afterload challenges andcardiac pacing all under trans-esophageal echo and trans-thoracicultrasound guidance to optimize repair.

FIG. 33 illustrates an expanded view of the finished repair region. Astaple 350 is fixedly attached to fiber 312 at position 345. Pullingcable 312 through various loops 353 of staples 350 causes pulling of theannulus into a smaller diameter, thus closing the valve from aninitially larger diameter, dotted outline 217, to a smaller diameter,solid outline in FIG. 32 at 217.

An alternate embodiment of a staple is illustrated in FIG. 34. Staple362 may be an elastic-like staple, such as a nitinol staple. Staple 362is normally biased to a closed position. A delivery system employs rod364, or the like, to hold staple 362 open. As the rod is movedlongitudinally to the array, each staple in sequence is sprung closed.Such an arrangement would avoid the necessity of a clamping mechanism352 as illustrated in FIG. 31.

FIGS. 35A and 35B illustrate other embodiments of an outer catheter 550and an inner catheter 554 extending through septal wall 560. Theseembodiments illustrate the outer (guide) catheter as a robotic catheter.It is understood that the instrument embodiments of FIGS. 20 and 32 mayalso encompass systems where the guide shaft is robotic. In FIG. 30, theguide catheter is also robotic. In FIGS. 35A and 35B, arrow 557indicates rotation of outer catheter 550, and arrow 559 indicatesflexing of outer catheter 550. In FIGS. 35A and 35B, inner catheter 554can experience linear motion along the co-axis (arrow 562) androtational motion (arrow 564). The outer catheter 550 may also becapable of independent linear translation. FIG. 35A illustrates innercatheter 554 as being capable of a controlled flex or bend, i.e. innercatheter 554 has a controlled flexible segment. Thus, the inner catheterof FIG. 35A is capable of deflecting in the direction of arrow 566.

FIG. 38 illustrates another embodiment of a catheter. Catheter 402supports dumbbell-shaped balloon 414. As illustrated in FIG. 39,catheter 402 can be introduced into the left ventricle 218 directedupwardly with balloon 414 disposed at mitral valve 210. The mitral valve210 separates the left ventricle 218 from the left atrium 220. As shownin FIG. 39, associated with the mitral valve is a ring of relativelytough tissue (the annulus) just above the top of valve leaflets 213.

FIG. 36 shows a cross-sectional view of the use of catheter 402 andballoon 414 for mitral valve repair. FIG. 36 shows the plurality ofperipherally disposed anchor pins 405. FIG. 36A shows each anchor pincomprising a piercing end 426 and a loop end 428. A fiber or tether 408,as illustrated in FIGS. 36 and 37 extends through each of the loop ends428 and has its ends at 409 free to extend through the catheter 402 toan external site where the tether can be tightened, as will be describedin further detail hereinafter.

FIG. 37 also shows the position wherein pins 405 have been inserted intowall 247, which is a section of the ring of the mitral valve just abovethe leaflets. Pulling tether ends 409 together can close the ring, thuspulling loop ends 428 into a smaller diameter. This smaller diameterreduces the diameter of the ring of the mitral valve so as to minimizeor prevent valve regurgitation.

Initially, FIGS. 38 and 39 illustrates balloon 314 positioned at adesired location and in a deflated state. FIG. 38 illustrates pins 405disposed about a center section of balloon 414. In the rest or deflatedposition as illustrated in FIG. 38, the pins disposed at their mostinner diameter. This innermost diameter state is also represented in thecross-sectional view of FIG. 36. Tether 408 may extend by way ofcatheter 402 to an external site where it can be operated, e.g. outsidethe body.

Once the catheter and balloon are in place, such as illustrated in FIG.39, the balloon is inflated by a balloon inflation lumen in thedirection of arrow 439 in FIG. 40. Arrangements for inflating balloonsare well known and are practiced, for example, in the angioplasty field.

Inflation pressure may be coupled by way of the port 441 to the interiorof balloon 414 causing the balloon to expand. In FIG. 40 the balloon isshown only partially expanded. When fully expanded, the anchor pins 405extend to the ring just above the leaflets as indicted at 445 in FIG.40. The corresponding cross-sectional view is shown in FIG. 37,depicting the anchor pins 405 penetrating and anchoring the tissue. FIG.37 illustrates a placement of tether ends 409. As the trigone portion ofthe base ring of the mitral valve is the most stable portion of thering, it is preferred that tether ends 409 leave the loop atapproximately the trigone area. In this way the drawing in of thediameter of the ring is more effective.

After the anchors are seated, as illustrated in FIG. 37, tether 408 canbe tightened, thereby pulling the tissue together so as to repair themitral valve and reduce or eliminate valve regurgitation.

Several different techniques may be used for guiding the catheter 402.For example, transesophageal ultrasound or transthorasic ultrasound maybe employed. Also, radiopaque dye fluoroscopy or electrophysiologictechniques may be employed for positioning of the catheter.

The tether can be placed about the mitral valve and tightened by usingcoaxial inner and outer catheters. The concepts illustrated in FIGS. 39and 40 may be practiced either with or without robotic control.

The aforementioned techniques for guiding the catheter may also be usedfor monitoring the effectiveness of the technique of the presentinvention. By monitoring the positioning of the balloon, one can assurethat the ends of the tether are preferably at the trigone area. Also, asthe tether is tightened, the surgeon may monitor the mitral valveactivity to determine whether the valve base ring has closed properly soas to reduce or eliminate valve regurgitation. Tether ends may besecured by knotting the ends thereof so as to hold the tether in aclosed position.

The techniques described herein may also be applied in other medicalprocedures involving repair of other anatomic body members. For example,the techniques described in FIGS. 17-40 may be used in closing,tightening, or constricting other anatomic conduits including, but notlimited to, lumens, valves, or sphincters. One example is in connectionwith drawing the sphincter into a smaller diameter. This smallerdiameter is particularly useful in controlling “acid reflux” byconstricting an expanded sphincter that couples between the stomach andesophagus. By tightening the sphincter, stomach acids are restricted tothe stomach and don't pass back toward the esophagus. Access for such atechnique may be via the patient's mouth. Of course, the techniques ofthe invention may also be applied in virtually any other medicalprocedures performed internally on the patient.

The present invention provides a relatively simple system, both in theconstruction and in its use. The capability to decouple components atthe drive unit and the receiver results in a readily portable andreadily manually insertable flexible instrument system that can behandled quite effectively by the surgeon or assistant when it is to beengaged with the patient. Only a minimal number of components arepositioned within the sterile field, enabling facile manipulation aboutthe surgical site. An advantage of the system of the present inventionis the decoupling nature of the system. In the system of the presentinvention, the instrument, drive unit and controller are inherentlydecoupled (attachable and detachable). The decouplable design enablesthe slave station to be readily portable. The instrument can bemaintained as sterile but the drive unit need not be sterilized.

The instrument of the present invention is relatively small because theactuators are not housed in any articulating structure in the system ofthis invention. Because the actuators are remote, they may be placedunder the operating table or in another convenient location and out ofthe sterile field. Because the drive unit is fixed and stationary, themotors may be arbitrary in size and configuration. Finally, the designallows multiple, specialized instruments to be coupled to the driveunit, allowing a user to design the instrument for particular surgicaldisciplines.

Having now described a limited number of embodiments of the presentinvention, it should now be apparent to those skilled in the art thatnumerous other embodiments and modifications thereof are contemplated asfalling within the scope of the present invention.

1. A robotic medical system, comprising: a support that is positionablerelative to a patient table; a carriage assembly removably mounted tothe support; a flexible guide shaft mounted on the carriage assembly andhaving a distal end configured for being disposed at a predeterminedlocation in a patient's body; a distal tool coupled to the flexibleguide shaft and configured for performing a medical procedure in thepatient's body; and a drive unit operatively coupled to the flexibleguide shaft through the carriage assembly to control the movement of theflexible guide shaft in at least one degree-of-freedom.
 2. The roboticmedical system of claim 1, wherein the support comprises a proximal endassembly configured for mounting to the patient table.
 3. The roboticmedical system of claim 1, wherein the carriage assembly comprises atleast one rail and a carriage slidably disposed on the at least onerail, and wherein the flexible guide shaft is coupled to the carriage.4. The robotic medical system of claim 1, wherein the at least onedegree-of-freedom comprises a plurality of degrees-of-freedom.
 5. Therobotic medical system of claim 1, wherein the drive unit is operativelycoupled to the distal tool through the carriage assembly to therebycontrol actuation of the distal tool.
 6. The robotic medical system ofclaim 1, wherein the at least one degree-of-freedom includes linearmotion of flexible guide shaft relative to the support.
 7. The roboticmedical system of claim 1, further comprising a remote controllerconfigured for directing the drive unit to control the movement of theflexible guide shaft in the at least one degree-of-freedom.
 8. Therobotic medical system of claim 7, wherein the remote controller has auser interface for receiving commands from a user, and wherein movementsof the flexible guide shaft correspond to movements made at the userinterface.
 9. A robotic medical system, comprising: a support arm thatis positionable relative to a patient table; a carriage assemblyremovably mounted to the support arm; a surgical instrument mounted tothe carriage assembly, the surgical instrument carrying a distal toolconfigured for performing a medical procedure on a patient; a drive unitconfigured operatively coupled to the surgical instrument to control themovement of the surgical instrument in at least one degree-of-freedom;and a remote controller configured for directing the drive unit tocontrol the movement of the surgical instrument in the at least onedegree-of-freedom.
 10. The robotic medical system of claim 9, whereinthe at least one degree-of-freedom comprises a plurality ofdegrees-of-freedom.
 11. The robotic medical system of claim 9, whereinthe drive unit is further operatively coupled to the distal tool tothereby control actuation of the distal tool.
 12. The robotic medicalsystem of claim 9, wherein the at least one degree-of-freedom includeslinear movement of the surgical instrument relative to the support. 13.The robotic medical system of claim 9, wherein the remote controller hasa user interface for receiving commands from a user, and whereinmovements of the surgical instrument correspond to movements made at theuser interface.
 14. The robotic medical system of claim 9, wherein thesurgical instrument comprises a flexible guide shaft mounted on thecarriage assembly and having a distal end configured for being disposedat a predetermined location in a patient's body.